On a wet and windy night in November 1980 Mario Luisi was walking through sodden meadows by a river outside his home village of Burneside in the English Lake District. In the darkness he saw what he took to be a cow. Then he thought it might be a crudely constructed sheep shelter. But then he saw that the object was hovering 1 metre above the ground and looked like nothing so much as a distorted aeroplane. It was about the size of a helicopter and had what seemed to be a tailplane, but no wings. It bore strange symbols, the like of which Luisi had never seen before.

As he stared at the weird object glinting in the beam of his lantern, he became aware of a squelching sound. He realised that someone was approaching him across the soggy ground and turned the beam of the lantern in the direction of the sound. He saw two figures, apparently human, about 2 metres away, beside an old oak tree. They were wearing dark, skin-tight suits. At that instant one of them, apparently female, raised a small pencil-shaped object in her hand. A bright light shot out from it, striking the face of Luisi's lantern. The glass front shattered and as Luisi watched, the metal reflector became warped and twisted. The remainder of Mario Luisi's encounter took place by the light from a paper mill on the other side of the river. The female figure spoke to him, telling him that she and her companion meant no harm and had come to the Earth in peace. (Presumably, then, their "attack" was a defensive measure against what they had taken to be a weapon - the lantern.)

Luisi was told that he must not reveal the strange symbols on the ship, nor those on the lapel badges worn by both figures. He could only stare, his legs shaking, as the two beings, who were fair-skinned, entered their craft by means of a ladder that descended from it. Presently the object shot upwards, leaving a glow in the sky. The encounter left Mario Luisi with a memory that would change his outlook on life. For him, at least, there was no longer any doubt no need to question whether the human race is alone in the Universe. He "knew" that we are not.

This problem has fascinated mankind ever since it was realised, in the 16th century, that the planets are other worlds and the stars are other suns, possibly possessing their own planets. The human race seems to abhor the idea of being alone in an immeasurably vast Universe. This sentiment was exploited to great effect by Steven Spielberg's epic film "Close Encounters of the Third Kind", which was released in 1977. Spielberg brought the idea vividly to life. He himself is keenly interested in UFO's and is associated with the Centre for UFO Studies, in Evanston, Illinois, USA, which is run by J. Allen Hynek.

The most fantastic type of evidence on the question consists of the numerous accounts of the close encounters of the forth kind of which Mario Luisi's is one. These go beyond close encounters of the third kind, in which aliens are merely seen: witnesses claim to have met, talked to, travelled in company with, or even been abducted by creatures not of this world. Four varieties of close encounters of the fourth kind have been distinguished. Mario Luisi's experience is typical of type A, which embraces straightforward encounters where the witness fully remembers what took place. There are no memory blocks, no intervals of time that the subject is unable to recall, no obvious reason to doubt that the experience was of something completely real. It is just as much a part of the sequence of events as getting up that morning.

These type A events are the most sober evidence for the reality of aliens. And they are by no means rare. Although close encounters of the fourth kind as a whole make up no more than about 1 or 2 per cent of the total number of UFO reports made each year, this still amounts to many hundreds of cases since the Second World War. They come from almost every country and all social groups. And over half of these encounters are of type A. It is thought that they could be even more common than the figures suggest, for there is evidence that witnesses are unwilling to talk about this kind of experience. Seeing an unidentified light in the sky is almost commonplace these days and people are more willing to report it than they once were. But talking to a creature from another world is, for many people, something to keep quiet about. This is unfortunate, since it means that researchers are unsure of the true scale of the phenomenon. But the information supplied by courageous witnesses is sufficient to indicate that something truly extraordinary is going on.

But serious problems arise, even in these seemingly rational type A accounts. The Mario Luisi case is typical in this respect. He volunteered the lantern for scientific study. The results of two independent analyses were identical: in the opinion of experts the damage was done by ordinary means, probably by a blow- torch. Had Luisi concocted his story and damaged the lantern himself, it would have been odd for him to be so co-operative. And it is not possible to disprove his claim, by which he stands, that the lantern was struck by a beam from an alien weapon. Certain other points in Mario Luisi's story support his claims. But support is not proof: and we never do get proof in cases of close encounters of the fourth kind that a witness is not lying.

The difficulty, of course, is that even if the witness is telling the truth, there is no guarantee that his alien contacts are not using materials and technology indistinguishable from our own. Nevertheless, when what is presented as evidence could perfectly well be of earthly origin, one is bound to become suspicious.

A number of researchers have been conducting studies into close encounters of the fourth kind, analysing the features of the stories in detail. Type A cases stand out from the other reports in many ways. They tend to occur outside the usual surroundings of the witness in the open, perhaps in a field and so on. They happen at any time of the day, even though UFO's are predominantly nocturnal. The average number of witnesses per case is well below the average for all UFO cases but close to the average for all close encounters of the fourth kind.

Photographs purporting to show alien beings are, disappointingly, rare. This seems highly significant when it is remembered that UFO photographs are very numerous. If the number of pictures of aliens where of the same proportion as the number proof contact cases, 1 or 2 percent then we would have a great deal of material to work on. In fact there are no more than two or three photographs and none that, beyond reasonable doubt, link an alien being with a UFO.

Yet we cannot complacently dismiss the phenomenon as unreal. For there are cases in which several witnesses see aliens. One example occurred on 3rd March 1980, at Rio Piedras, Puerto Rico. Two teenage children, Vivian and Jose Rodriguez, were woken at 3.3O a.m. by a barking dog. They looked through the window of their farm to see five strange creatures, with pointed ears and webbed feet, wearing tight-fitting clothes. The aliens seemed interested in the family's chickens. No UFO was observed by the children.

Next day it was discovered that at the same time of night two men nearby had seen the same creatures. The witnesses had been sleeping in a parked car, resting during a long journey. They had woken up and had seen a large domed object on the ground. Beings fitting the description given by the children had emerged from the object and headed in the direction of the Rodriguez farm. Such a story, if true, is very hard to explain as anything other than a real, physical event. The apparent subjectivity of these type A cases should not be over-stressed.

The second group of contact cases, type B is quite different. The aliens involved are often called "bedroom visitors" because as many of them make their appearance in the bedroom; the witnesses usually claim to have experienced the encounter while wide awake. These encounters have a good deal in common with ghost sightings that happen in the bedroom. What distinguishes these events from type A cases is that they possess obvious distortions of reality parts of the sequence of events are completely forgotten, there are jumps in the story from one scene of action to another, as in a film or a dream. The reality of the events is much more doubtful than that of the type A cases.

For example, on 5th January 1980 a 33-year-old house-painter awoke at 5 a.m. In his bedroom at Trowbridge, Wiltshire, in Southern England. He saw a glowing green figure, 2.1 metres tall, at the foot of his bed. It looked more like a projected image than a solid figure. The alien told the witness that the people to whom he belonged regularly shipped human beings off to other worlds in order to colonise them. When a planet became overcrowded they started a war in order to reduce the population. This behaviour seemed to be in conflict with other efforts that they were making to protect us: it seemed that our planet was liable to split in half and the alien visitors were desperately trying to plug the cracks by injecting a liquid cement from their remotely controlled space vehicles!

Interestingly, the witness's wife was in bed beside him all this time, yet she did not awaken, nor did it occur to him to disturb her. It seems most unlikely that anyone would make up such a story and expect anyone to believe it. It is not necessary to doubt the witness's sincerity but neither is it necessary to take this weird story at all seriously. Type B cases are rarer than type A - they form about a quarter of all contact reports. They are far more subjective, since they are almost exclusively single-witness encounters. By far the majority of them occur in the home or its immediate surroundings fully two thirds of the cases occur in the bedroom. And most of them happen in the early hours of the morning.

This seems to suggest that the two types of contact are different in nature: type A sound like real contacts with something physical type B sound like some kind of hallucination. It seems a plausible working hypothesis, though there are cases in which it is hard to decide whether a case belongs to type A or type B. The third category of contact report, type C, involves an experience that is not immediately remembered. The experience of an English family, the Days, will illustrate how disturbing this can be.

One evening in October 1974, John and Sue Day were driving to their home at Aveley, in Essex. They had been visiting relatives and were now hurrying, hoping to catch a late night television play. Their three children were with them and fell asleep during the journey. Then their parents saw a blue light pacing the car. They watched it for some time but were unable to identify what it could be. Then the light disappeared and the car turned a corner and ran into a well-defined bank of eerie green mist. The Days were in the mist for only a few seconds, but the car radio sparked and crackled. John instantly yanked out its wires to prevent a fire hazard. After recovering their composure the family drove the few hundred yards to their home.

When they got home they switched on their television set, but the screen remained blank. It was two hours later than they had thought and the station had closed down. Someone or something had stolen a piece of their lives. The family were naturally perturbed by this mysterious time lapse. Over the next few months they had several dreams about it fleeting visions of weird faces, occasional strange impulses to refrain from eating meat or drinking alcohol. Eventually two UFO investigators, Andy Collin's and Barry King, heard of the event. They brought in the help of a medical hypnotist Leonard Wilder, a London dentist. The Days underwent regression hypnosis in the hope of retrieving memories of that missing time. And the memories came.

Under hypnosis John and Sue told stories that were in close agreement. However, there were some differences, and they did indeed claim to have been separated for much of the "missing" time. The children also seemed to recall the experience in subsequent dreams.

A UFO had landed and the family had been taken on board. They were given medical examinations and shown around the craft. They were informed about its propulsion system and the way of life and intentions of the alien visitors. Eventually they were returned to their car by a process akin to astral projection and they continued their journey. But their lives could never be the same again. To those who interviewed them, the Day family seemed a group of pleasant and sincere people who had never tried to force their story onto anyone, or to make money from it. Something quite certainly happened to them that night... but what?

In type C contacts, something blocks the witnesses' memory. Occasionally recall of the "missing" events is triggered by normal events. Not infrequently the subject has dreams that hint at what took place during the missing minutes, hours or even, in a very few instances, days. But the most common means by which the floodgates of memory are opened is regression hypnosis.

Type C abductions are remarkably consistent. One in five stories of alien contact involves amnesia and alleged abduction. Type C cases are more subjective than ordinary UFO sightings, since they tend to involve fewer witnesses; but they have a higher number of witnesses per case than type B or, surprisingly, type A cases. The aliens involved usually resemble human beings and are usually the normal human size, or larger; there are very few entities of small stature, unlike those featured in type A cases. The most common time for type C incidents to occur is between about 10 p.m. and midnight. And a very large proportion of them involve young couples driving cars along quiet roads (quite often carrying children with them). It is also common for one or more of the witnesses to have a history of strange experiences witnessing ghosts or poltergeists, for example.

And the way of life of the subjects may undergo drastic changes, even before the memory of an apparent abduction is at last retrieved and the cause of the changes made apparent.

The fourth group of close encounters of the fourth kind comprises very few cases. It consists of those experiences in which the encounter does not seem to involve physical contact: communication is by means of telepathy, automatic writing, or something of the kind. We shall not these in this article. We shall try instead to see whether among all the details of the cases of types A, B and C there is a clue to the reasons why such experiences occur.

Hypnosis is still a controversial subject. Its significance becomes even more obscure when it is used to recover the blocked memories of a witness in a UFO contact case. Experts dispute the origin of the images that come to the mind of such a person in a hypnotic trance. Is the subject's psychic potential boosted? Does he become able to dredge information from the collective unconscious, potentially becoming aware of everything that has ever happened anywhere at all? Or is the abduction memory that comes to the witness simply a respinning by his mind of a story once read and now forgotten the re-creation of a modern myth?

For certainly alien beings and their spacecraft have attained the commanding status of myths of our time, whatever the reality that lies behind them. Or does regression hypnosis simply free the memory so that the barriers to recall can be hurdled and the "missing" period relived? There is a very difficult problem of assessment whenever a witness in a type C case retrieves a "memory". What is its true significance?

A case similar to that of the Day family occurred in June 1978, again in England. A young couple, their children and another adult were involved. The alleged abduction took place during a car journey in Oxfordshire; again there were many similarities with other abduction stories: for example, three-dimensional ("holographic") shows were displayed to the witnesses. But the story as a whole was quite unlike any of the 100 or more other type C cases that have been documented by UFOlogists.

The aliens looked humanoid indeed, very like those seen by John and Sue Day and they told of the origin of their race on Earth and their emigration to the planet Janos. Now a horrific natural disaster had precipitated their flight back to Earth. They wish to move in with us... a million or so refugees from this cosmic catastrophe. What is interesting about this case is partly, how it resembles in outline other incidents, such as the Day case (which had received publicity in the British press). But more importantly, the interests, attitudes and manner of questioning of the investigators found their way into the story that was told as if the hypnotised witnesses were picking up "cues" from the investigators and fitting them into their accounts as they told them. This is rather like the game in which you are given a series of objects say, a book, a pen, a candlestick and a toy balloon and are asked to use your imagination to weave a story in which they all figure. This curious problem is further illustrated by the experiences of young Gaynor Sunderland, from Oakenholt in North Wales. She and her family had many weird encounters, including contacts with aliens who, again, looked rather like the ones met by others who reported similar experiences.

On one occasion Gaynor was having trouble sleeping because she kept seeing two aliens one male, one female. (Later she found that they were named Pars and Arna.) I was then investigating the case and I suggested to her mother, Marion Sunderland, that she could tell Gaynor a white lie. Gaynor was told: "If you put a loaded camera in the bedroom the aliens will not come because they do not like having their pictures taken." A couple of nights later Gaynor was allegedly abducted to another world and taken on a tour of a city there by Arna and Pars. She was told that she was not really there: the experience was in her subconscious mind, a kind of dream. Yet the aliens maintained: "We did not come to you because of the camera." It is highly paradoxical that an alien entity should first admit to being a product of the unconscious mind and then claim to dislike being photographed. It seems that Gaynor's mind somehow wove the idea concerning the camera into her experience of the trip to another world. But she remained convinced of the reality of her experience and said it was far more vivid than a typical dream.

We sometimes find that the initial stimulus for an abduction experience is an event that can be explained straightforwardly. This casts doubt on the remainder of the account provided by the witnesses. One of the most famous type C cases involved an American couple, Betty and Barney Hill, who were returning from holiday across the mountains of New England during September 1961. A mysterious "craft" followed them and then came down nearby; Barney Hill watched it through binoculars before driving away in panic. All the classic features of such incidents were there: a psychic witness (Betty phenomena throughout her life); a blank in their memory of events; strange dreams afterwards; and finally, under hypnosis, memories of abduction and medical examination on board the UFO. Yet it has been argued very convincingly that the light in the sky that marked the beginning of the whole train of events was nothing more than the planet Jupiter.

This does not in itself tell us anything about the reality of the experience; witnesses often link completely unassociated events in their recollections of some incident, simply because those events happened to occur at roughly the same time. But it is just part of the process by which human beings misperceive events, distort their memories of them and come to mistaken conclusions about them later.

We should bear this complex process of interpretation and misinterpretation in mind as we consider the appearance presented by aliens and their craft in contact reports. What should we expect extra-terrestrial life forms to look like? This is a very hard question to answer, since our only examples of life come from one planet the Earth. Yet when we see the amazing range of species hosted by our environment and recognise that mankind is just a link in a long evolutionary

chain in which an even greater diversity of forms has existed, we find little reason to suppose that alien beings should look like us. Admittedly the humanoid form is well-adapted to a wide range of environments on the Earth's surface, and it may well be common on other Earth-like planets throughout the Galaxy; but the human form is presumably not a necessary condition for dominance. Since other worlds would have a great range of habitats, and local conditions would vary greatly, life there would undoubtedly be equally diverse.

Carl Sagan, the eminent astronomer. has even proposed possible life forms capable of surviving on Jupiter: such as living balloons in the oceans of water that may exist in the warm depths of the planet, below the perpetually frozen clouds that we see. The last thing we would expect is a menagerie of alien races looking more or less like us and yet, according to contactee's, this is precisely what we do find. cases involve creatures that are not humanoid. Such beings as the giant white maggots that crawled across a road in Yssandon, France, in 1960, during a UFO sighting, are rare. There are three distinct groupings among the humanoids that form the bulk of the data:

SMALL - Below 1.5 metres tall and usually about 1 metre);

MEDIUM - 1.5 to 1.8 metres); and

LARGE - Up to about 2.1 to 2.4 metres.

In type C (bedroom visitors) encounters, the entities witnessed are fairly normal, with a slight tendency to larger sizes. In no fewer than 41 per cent of type A cases, on the other hand, the entities seen are small. There are other fairly common features, such as large eyes, fair skins and annular features. But other factors, such as clothes, show great diversity.

One might not consider this to be a problem. After all, people on Earth wear a wide variety of clothes and human beings of different ages, races and sexes are extraordinarily diverse. But the difficulty with contact cases is more fundamental: the aliens as described are just too much like us. They usually speak the language of the contactee, whether it be English or Serbo-Croat. Nearly always they speak it faultlessly and without any noticeable accent. This means, of course, that they are speaking in the same accent as the contactee himself (a vital, but usually overlooked, point).

Their fashions, too, are far too similar to those on Earth. It seems nonsensical to imagine that an alien from a planet light years away should wear a cloak buttoned at the neck and sport a badge on the breast of a jump-suit-style garment. Yet this is what contactee's claim and it is all too reminiscent of the limited imaginations (or wardrobe budgets) of science-fiction film-makers.

If a witness asks for the origins of an alien, he is almost invariably told that the entity comes from space. In the earliest contacts the aliens home planets belonged to our solar system Mars, Venus, Saturn and so on. Now we know that humanoid life on these worlds is impossible and present-day contactee's are told the aliens come from planets circling distant stars. As yet, of course, science knows little about the very existence of such planets, let alone their suitability for life. What is it like inside an alien craft? The witnesses answers to this question also raise grave questions about the nature of their experience. Imagine a Stone Age man transported through time and taken onto the flight deck of a Concorde airliner. The instruments and controls would be quite incomprehensible to him. How could he possibly describe what he saw in any intelligible way, knowing nothing of the purpose and importance of what he was seeing? This would be the predicament of any Earth-dweller taken inside an alien starship.

Yet these amazingly advanced visitors, who traverse interstellar space at a whim, apparently do so in spaceships that would not look out of place in one of our engineering museums. They use levers and valves, wires and old-fashioned bulky computers. They have flashing lights, in the manner of Star Trek and Doctor Who. They are slow in catching up with our primitive technology. They are just getting round to using lasers and holograms (which they did not have before we did) and they do not as yet have the liquid crystal displays that are now

standard on our watches and calculators. What is more, their spaceships are always breaking down... Not infrequently the aliens enlist the help of Earth-dwellers to sort out their problems. Once they asked an eight-year-old boy to fix their propulsion unit. Evidently the origin of all this is not the face-value explanation beloved of the alien spacecraft theorists.

Once the contactee's are aboard, the aliens usually carry out a medical examination. Taking blood samples is an integral part of this. The Irish UFOlogist John Hind points out that the doctor is the symbol of authority who plays the greatest role in the lives of many people. There seem to be significant resemblance's between these examinations by aliens and the contactee's previous experience of medical treatment. One Canadian abduction appeared to feature a replay of an appendectomy that the witness had earlier undergone.

The memory blocks in type C cases present an interesting problem. If aliens can suppress memories, why do they do it in such an ineffective way? The memories usually filter through spontaneously and are easily retrievable in full by hypnosis. Why block them at all? Unless the memory block in fact works successfully in most cases implying that there are thousands of people who are abducted and have no inkling of the fact afterwards.

Whatever the reason for these memory blocks, the lapse of time between the original occurrence and its subsequent recall severely impedes the investigation of the case. And this, of course, may be the most significant function that the memory loss serves. When aliens give us messages they are almost always of one form: warnings about the future of the Earth, with hints of nuclear war and impending doom. If only we were sometimes given something startling and original a new scientific theory, a helpful invention, a cure for cancer. But no; we are told that, because of our nuclear tests, "the balance of the Universe is being disturbed".

Occasionally there is some light relief. In spring 1978 a Red Army officer was abducted by the shores of the Pyrogovskoye Lake in Russia. Once he had got used to his humanoid hosts, he suggested they ought to toast this cross-cultural contact with a suitable drink. They did not understand. So he sketched out the chemical structure of alcohol and the aliens retired and immediately made some. "How is it that such a highly developed civilisation does not use something like this?" the Russian asked. "Maybe if we had used it we would not be so highly developed," was the response.

A teetotal message in the form of a joke makes a welcome change from the usual run of communications from other worlds. Aliens beings must exist somewhere in the Universe, in some form or other. Of this there is little doubt. The problem confronting us is whether the evidence we possess proves that some of these aliens are visiting the Earth now. If this is so, then proving the fact would be of the utmost significance. It would be perhaps the most momentous occasion in the history of the world.

But we do not possess photographs, movie films or tape recordings of aliens, or artefacts manufactured on another world... anything that goes beyond mere testimony. In view of this paucity of hard evidence we can hardly say, with any definiteness, whether aliens are or are not visiting us . We can only make a reasoned assessment of the facts. The dilemmas posed by close encounters of the fourth kind are starkly illustrated by a case that occurred in the north of England on 28th November l980. Police Constable Alan Godfrey had been called out to pursue some cows that were allegedly roaming a housing estate. By 5.15 a.m., still not having found them, he was ready to give up the search. While making one last trip in his patrol car before coming off duty, he saw a glow on the road ahead. He instantly thought of a works bus that regularly travelled the route and idly wondered why it was a little early. Then, as he approached the glow, it became obvious that he had been wrong.

The object that confronted PC Godfrey was like a spinning top with windows. It was hovering just above the road surface, spanning the gap between two lamp posts and it was rotating. He could see his headlights reflected in the metallic surface of the object. He could see leaves on the roadside bushes moving in the vortex created by its rotation. The road surface, soaking wet in other places, was dry in blotchy patches directly beneath the object. There was no doubt in his mind that the object was real. Maintaining the traditional calm of the British "bobby", the officer propped his clipboard on the windscreen and carefully sketched the object. But then something inexplicable happened. He suddenly found himself further down the road, driving the car away from the scene. Nonplussed, he turned the car round and drove past the spot, now deserted, where the object had been. He carried on the short distance into town and collected a colleague. Only at this point did he notice the time.

Somewhere, since the moment he first saw the UFO, 10O minutes had disappeared. Constable Godfrey had a dim memory, however of a strange voice saying: "This is not for your eyes. You will forget it." Additional fragmentary recollections gradually filtered back to him until, nine months after the incident and with the help of UFOlogists, he underwent regression hypnosis. This was conducted by an eminently qualified and rather sceptical psychiatrist and what appeared to be a coherent memory of the incident emerged. The story was of the usual type: the officer had been taken on board the UFO and given a medical examination by two distinct types of humanoid creature one tall, the other small and somewhat ugly. Remarkably, this is almost exactly what the Day family claimed happened to them during their abduction at Aveley in Essex. In

fact, contact cases reported from Britain share such similarities in many features. Cases reported from other countries, on the other hand, show different similarities among themselves.

What happened to the police constable? Is he lying to us? If not, did he have an hallucination or did he undergo the events he described? Or was it something between hallucination and straightforward experience a distortion or misinterpretation of some extraordinary events? There happens to be unusual and powerful support for the "face-value" interpretation of the story. Four police officers on patrol 13 kilometres away had to duck as a UFO streaked low over their heads, moving directly towards the town near which the encounter took place. And a caretaker lighting a school's boilers saw in the direction of the town an object that fitted PC Godfrey's description, climbing into the sky. These stories were reported independently while the police officer was still reporting what he had just observed.

When faced with an issue like this, most people take sharply contrasting attitudes. Some would want to believe that aliens were involved. Others would deny that this was possible and would cling to the hallucination theory. Unfortunately these two hypotheses have points both in their favour and against them. So let us survey some of the difficulties that the various answers face. Why do aliens look like us? Why do they behave like us? Why do they mirror our social and scientific developments? Why do they never tell us anything valuable to which we do not already have access? These problems are curiously like those involved in alleged memories of past lives, spirit messages and other demonstrations of survival of death. It is surely not without significance that the common factor in these cases is the frequent use of regression hypnosis and the role of the human mind. Taken together, these facts suggest a mental origin for these strange experiences.

To this type of evidence we should add research into lucid dreams. These are dreams in which the dreamer is fully aware that he is dreaming. Often the course of the dream can be controlled by conscious effort. Such dreams are rare and seem to overlap with such phenomena as hypnagogic imagery (the images, often compellingly "real", that come when we are between waking and sleep). Although they seem so real at the time, lucid dreams and hypnagogic images give away their "unreal" nature in various subtle hints. For example, the subject does not react with normal responses. He may feel no fear, despite the weirdness of the experience. He will not wake up a sleeping bed partner to witness the events. In one case a person had such an experience, in which he thought an atomic bomb had just exploded in his garden. His response was to yawn and fall asleep. The behaviour of contact case witnesses is often like this.

Interestingly, such symptoms also occur in hallucinations that follow long periods of sensory deprivation. When a person is kept in darkness and silence and even his sense of touch is deprived of its normal stimulation because his hands are enveloped in special gloves, his mind starts to manufacture its own "perceptions" hallucinations of sound, sight and touch. When we consider the usual setting of a type C contact night-time, a tired driver, a lonely country road and the sudden appearance of a slightly unusual sight, such as a bright light in the sky it does not stretch credulity very far to suggest that these could be hallucinations brought about by the lack of sensory stimulation.

In the USA Dr Alvin Lawson, a professor of English at the University of California, has conducted experiments that are relevant to the hallucination theory. He advertised for people of a "creative" turn of mind to take part in an unspecified experiment. He screened out all those who seemed to have a knowledge of, or interest in, UFO's. The rest were asked to imagine, under hypnosis, that they were being abducted by aliens. They were led on with certain key questions and the results, he claimed, were so closely akin to the stories told of allegedly real abductions that it was likely that these also were, wholly or in part, subconscious fantasies.

These different types of evidence constitute impressive support for the contention that alien contacts are hallucinatory. But unfortunately there is a fair amount of negative evidence too. Some contact experiences are shared; while collective hallucinations can occur, they are not well-understood and some encounters stretch this hypothesis to breaking point. One Italian type A case involved seven witnesses; one British type A involved four. In some cases, such as those in Puerto Rico and that involving the English police officer, there is at least some degree of independent corroboration.

Alvin Lawson's work, as he himself recognised, showed major differences between allegedly real abductions and imagined ones, as well as similarities. When, in a UFO contact case, memories emerge by way of hypnosis, they are almost invariably associated with very strong emotions, more consistent with the memory of area event than a fantasy. The "abductions" imagined in the laboratory did not display this effect and in general those who took part in the experiment knew afterwards that they had been fantasising. Contact witnesses are never in any doubt that their regression memory is of a real event. It can still be argued, of course, that the remembered event, though real, is purely "mental" a hallucination or dream.

We must also consider the frequent reports of physical effects on a witness's body, such as burns on the skin. Marks on the ground sometimes accompany these cases as well. But, on the other hand, there is almost no photographic support for the contact witnesses' stories and physical effects can be produced psychosomatically. Looking at more subtle features of the accounts, considerable consistency and a kind of lucid cohesiveness appear in all but the type B "bedroom visitor" cases. This tends to make the UFO investigator doubt that he is dealing with experiences more akin to dreams than reality.

It is very difficult to sort out these contradictory elements. Perhaps the fairest judgement we can make at present is to say that type B experiences seem more like vivid hallucinations than reality. Type C ("memory block") cases have elements suggesting hallucinations but, unlike type B experiences, offer some data that cast doubt on this assumption. If type C cases are indeed hallucinations, they seem to be of a unique type almost a hybrid between dream and reality. As for the most common contact cases, type A, they are the least like hallucinations. While they are full of problems, we cannot explain them as hallucinations with any degree of confidence. What of the other extreme? Are these contacts extra-terrestrial in nature? This, the "face-value" hypothesis, implies that hundreds of different races (most of them not very imaginative variants on ourselves), from many different worlds, are taking a great deal of interest in the Earth.

They perform medical examinations interminably and gather up endless cargoes of soil and rock samples. For no apparent reason the Earth is the Galaxy's Grand Central Station. The sceptics invariably ask why the aliens don't contact someone important. Why not land on the White House lawn and thus dispel all doubts? Gaynor Sunderland asked Arna, one of the aliens she claimed to have met, this very question. She was told that people in authority had so much credibility to lose that there was no point in contacting them, although this had been tried on a few occasions. Fear of the consequences kept such people silent. Instead the aliens pursue a policy of contacting children or simple folk, knowing that some of these will brave the ridicule and speak out.

This argument makes an intriguing amount of sense. Widespread belief in the existence of alien life is the only tangible result of decades of UFO stories. A slow, covert process of conditioning world opinion to the idea of extra-terrestrial visitors fits well with the "provocative but not probative" evidence that we possess. Solid proof would be detrimental to such a policy: it would be impounded, or hidden, or denied outright. Suggestive indications, on the other hand, avoid the unwelcome attention of authority while providing a stimulus to continued interest and promoting the long, slow build-up of belief. Even the confusing and ridiculous behaviour of the aliens would fit this theory. In the end the only people who will not be convinced that aliens come from space will be the UFO investigators themselves!

A great deal of fascinating work remains before we can hope to know the truth. There is no hard evidence that a superior intelligence has made contact with the Earth but we do have suggestive hints that this might be true. And, since most of us would wish UFO's to come from space, our judgement is clouded by an enormous emotional bias.

"Frenchman back to Earth with a bump" was the headline in the London Times-and across the world the media reported the news with the same uncertainty whether to take it seriously or not. But this much was certain: Franck Fontaine, who had allegedly been kidnapped by a UFO a week before, had been restored to friends, family and a wondering world in the early hours of Monday, 3rd December 1979.

Where had he spent those seven days? The world, hoping for a story that would make the Moon landing seem tame, was disappointed. Fontaine's recollections were few and confused. It seemed to him he had simply dropped off to sleep for half an hour: he was astonished and dismayed to find he had been away for a week. He attributed the strange images in his mind to dreams: he was bewildered to learn that he might have been abducted by extra-terrestrial aliens and carried to their distant world.

Fontaine was no less dismayed to find himself the focus of the world's attention. During his seven-day absence, it had been his friends Salomon N'Diaye and Jean Pierre Prevost, witnesses of his abduction, who had been the objects of attention. Ever since their first startling telephone call to the police "A friend of mine's just been carried off by a UFO!" they had been subjected to interrogation by the police, by the press and by UFO investigative groups ranging from the scientific to the bizarre. If Fontaine's return brought renewed publicity and fresh problems, at least it cleared them of the suspicion that they were responsible for their friend's disappearance perhaps even his death.

The life-style of the three young men was not of a sort to dispel suspicion. All three Prevost, aged 26, N'Diaye, 25, Fontaine, 18 scraped an uncertain living by selling jeans in street markets. They drove an old car that was unlicensed and uninsured, none of them having a driving licence. Prevost was a self declared anarchist. He and N'Diaye lived next door to each other in a modern block at Cergy-Pontoise on the outskirts of Paris. Fontaine lived 3 kilometres away. According to their account, Fontaine had spent Sunday evening in Provost's flat because they wanted to be up by 3.30 a.m. to travel the 60 kilometres to the street market at Gisors. The market didn't start until 8 a.m. but they wanted a good place. Besides, their Taunus estate car had been acting up lately, so they thought it prudent to allow extra time. At 3.30, after only about four hours sleep, they were up and ready to load the car with clothes.

First, though, they gave the car a push start to make sure the engine would function. Having got it going, they decided that Fontaine should stay in the car to make sure it didn't stop again while the other two got on with the loading. Fontaine had leisure to look about him and so it was that he noticed a brilliant light in the sky some distance away. When his companions arrived with their next load, he pointed the object out. It was cylindrical in shape, but otherwise unidentifiable. When it moved behind the block of flats, N'Diaye rushed upstairs to fetch a camera, thinking he might take a photograph of the object to sell to the newspapers. Prevost went in to get another load of clothing while Fontaine, hoping for another view of the mysterious object, drove up onto the main road that ran close by the flats.

Hearing the sound of the moving vehicle, his companions looked out of the windows of their respective flats. Both saw that Fontaine had stopped the car on the main road and noted that the engine was no longer running. Prevost, angry because they would probably have to push-start the car a second time, rushed downstairs again. He called to N'Diaye to forget about his camera because the UFO had vanished. N'Diaye came after him saying that in any case he had no film in his camera and adding that from his window it had looked as though the car was surrounded by a great ball of light.

Outdoors again, the two young men stopped in amazement: the rear of their car was enveloped in a sharply defined sphere of glowing mist, near which a number of smaller balls of light were moving about. While they stood watching, they saw the larger globe absorb all but one of the smaller ones. Then a beam of light emerged, which grew in size until it was like the cylindrical shape they had seen earlier. The large sphere seemed to enter this cylinder, which shot up into the sky and disappeared from sight.

The two hurried to the car, but found no sign of Fontaine. He was not in the car, in the road, or in the cabbage field beside the road. Prevost insisted on calling the police immediately and N'Diaye went off to do so. Prevost, remaining near the car, was the only witness to the last phase of the incident: a ball of light, like those previously moving about the car, seemed to push the car door shut. Then it too vanished.

Such was the account that the two young men gave to the police on their arrival a few minutes later. Because UFO sightings are a military matter in France, the police instructed Prevost and N'Diaye to inform the gendarmerie, which comes under the Ministry of National Defence. The two spent most of the day with the gendarmes, telling and retelling the story. The interrogators stopped for lunch, during which time the witnesses telephoned the press with their story.

Later, Commandant Courcoux of the Cergy gendarmerie told the press that there were no grounds for disbelieving the young men's story, that he had no doubt "something" had occurred and that he could give no indication of what that "something" might be. In a later interview he admitted, "We are swimming in fantasy."

For a week, that was all the world knew. During that week, the young men were questioned over and over again. Some people accepted the UFO story as it stood. Others suspected it to be a smoke-screen, perhaps a cunning plan to help Fontaine avoid doing his military service, perhaps something more sinister. But one fact stood out clearly: Prevost and N'Diaye had informed the police promptly and voluntarily. Given their backgrounds, wasn't this convincing proof of their sincerity?

When Fontaine gave his version of the story, there seemed no reason to question his sincerity either. He told how he had woken to find himself lying in the cabbage field. Getting to his feet, he realised he was just across the main road from the flats, close to where he had stopped the car to watch the UFO. But the car was no longer there. His first thought, as he hurried towards the still-darkened building, was that somebody had stolen their car and its valuable load of clothing. Neither Prevost nor N'Diaye was to be seen, so he rushed upstairs and rang the bell of Prevost's flat. When there was no reply, he went to N'Diaye's. A sleepy N'Diaye appeared, gawped at him in amazement, then flung his arms round him in delighted welcome. Fontaine, already surprised to find his friend in his night clothes, was even more amazed to learn that an entire week had gone by since the morning of the Gisors market.

He had little to tell the press or the police. The world's media reported his return but reserved judgement till they heard what the authorities had to say. But the police declared it was no longer their business: no crime had been committed. Apart from the inherent improbability of Fontaine's story, they had no reason to doubt his word or that of his friends.

So now it was up to the UFO organisations to see what further light could be thrown on the case. From the start, the witnesses had been besieged by the various French groups; there are dozens of these, most of them fiercely independent and reluctant to co-operate with the others. One of the most reputable of all is Control, to whom we owe most of what we now know of the inside story of the Cergy-Pontoise case.

But another group declared its interest before Control, while Fontaine was still missing: the Institute Mondial des Sciences Avances (World Institute of Advanced Sciences). Its co-founder and spokesman was the well-known science fiction writer and author of two books about UFO's, Jimmy Guieu. Before he had carried out an investigation, Guieu affirmed his belief in the story: "No question of it, Franck Fontaine has been abducted on board a UFO", he stated in an interview. "Admittedly I haven't questioned the young man's two companions, but I hold their account to be true a priori." Delighted to have their story accepted without reservation by so eminent an authority, Fontaine's two friends agreed to cooperate with Guieu. When Fontaine returned, he too was taken under IMSA'S wing. Guieu offered them a secret refuge in the south of France where they could work on a book together, Guieu writing it and all sharing the proceeds.

Guieu's book, Cergy-Pontoise UFO contacts, was rushed into print with astonishing speed, appearing a bare four months after Fontaine's return. Thanks to the combination of Guieu's name and the intense interest in the case, it was an instant best-seller. But readers hoping for a conclusive verdict were disappointed. The book was padded out by Guieu's journalistic style and digressive accounts of other cases and there was an almost total absence of first-hand testimony from the principal witness the abducted Fontaine whose story the world wanted to hear. Such revelations as the book contained were of quite another nature.

Guieu had hoped that Fontaine would be able to recall more of his adventure if he were hypnotised, but the young man obstinately refused to submit to hypnosis. Then Prevost suggested that he should be hypnotised instead. What resulted was truly amazing. It now emerged that Prevost, not Fontaine, had been the true object of alien interest. Now, speaking through him, the aliens explained all. Fontaine had simply been the means to establish communication: Prevost was the channel through whom they could communicate to help save Earth from impending disaster. The aliens identified themselves as "the intelligence's from beyond" but gave no clearer clue to the whereabouts of "beyond" than that it is "a planet not like yours". Their spokesman was Haurrio, a friendly if somewhat garrulous character.

In Guieu's book, Prevost becomes the hero of the story and the only evidence we have for the events is his word. His two companions seem to have become irrelevant. This book having raised more questions than it answered, much was hoped for when Prevost announced that he was writing his own account of the event. But The truth about the Cergy-Pontoise affair, published later that same year, was even less satisfactory. It was a rambling, incoherent farrago in which great doses of alien "philosophy" transmitted by Prevost show that pious platitudes about the need for more love and less science are not confined to planet Earth. There is virtually no mention of Franck Fontaine's abduction: indeed, he and Salomon N'Diaye are scarcely referred to. But Prevost's visit to a secret alien base is described in some detail and this gives us a good yardstick for evaluating the rest of the material. It seems that one morning soon after Fontaine's return, there was a ring at Prevost's door.

The caller was a travelling salesman, a total stranger who said he had to make a trip to Bourg-de-Sirod and invited Prevost to come along. Now, Bourg-de-Sirod is a small village near the Swiss border some 360 kilometres from Cergy. On the face of it, there is no conceivable reason why a salesman should go there, nor why he should think that Prevost might wish to go there given that they were strangers in the first place. However, there was a reason for interest by Prevost. Bourg-de-Sirod was a specially significant place for him because as a child he had gone to a summer camp nearby and had later worked there. More recently still, he and Fontaine had spent a camping holiday there. So Prevost, though surprised at the stranger's offer, cheerfully accepted it. The salesman dropped him off at the village and he set off up the hill towards a particular site that had always fascinated him a railway tunnel containing an abandoned train carriagefrom the Second World War.

Arriving at the tunnel in late evening, Prevost found that other people were there before him: a group of young men gathered round a fire in the open. One of them called out his name; he was from the Sahara and had recently written to Prevost. It turned out that he and the others had come there from many parts of the world, thanks to the "intelligence's from beyond". Each spoke his own language but was understood by the rest.

When Haurrio, the alien representative, arrived, he informed them that they had been chosen to spread the philosophy of the "intelligence's" on Earth. A beautiful female alien then took them on a tour of the tunnel, now being used as a UFO base. They saw several spacecraft, similar to ones that Prevost had seen as a child. After their tour, the young men returned to their camp fire and went to sleep on the ground which, on a December night in the mountains, must have been less than comfortable. Next morning Prevost found his friendly salesman waiting to chauffeur him back to Cergy.

Whether Jimmy Guieu and Jean-Pierre Prevost seriously expected their accounts to be believed, we may never know. But the more they provided in the way of checkable statements, the harder it became to accept the original account of the alleged abduction. Doubts grew even more when an investigative team from Control persisted in taking up the case without the co-operation of the witnesses checking all the conflicting statements and fragmented testimony as best they could. The abduction of Franck Fontaine by a UFO, though unsubstantiated by scientific evidence, seemed a plausible story on first hearing. Had he and his friends Jean-Pierre Prevost and Salomon N'Diaye been content to tell that story and nothing else, they might have convinced an interested world of its truth. But the two books on the case one by the well-known science fiction writer Jimmy Guieu and one by Prevost himself raised questions that cast suspicion on the entire affair.

Moreover, there were many interviews and conferences in which widely divergent material was put forward. And Prevost, who had pre-empted Fontaine as the hero of the Cergy-Pontoise UFO affair, even published a short-lived journal in which he kept the public informed of his continuing dialogue with the "intelligence's from beyond" who he claimed had contacted him. All this increased the doubts of the sceptics. Michel Piccin and his colleagues of the Control organisation had detected inconsistencies and contradictions in the witnesses statements from the start. And the more they probed, the more discrepancies they found.

It began with trivial, marginal matters, like Prevost's insistence that before the encounter he had no interest in or knowledge of UFO's. The Control investigators found that his brother was a French representative of the American UFO organisation APRO. Even if Prevost did not share his brother's interest in UFO's, he could hardly have been unaware of them. Besides, in his own book, Prevost had said that he saw several spacecraft similar to ones he had "seen as a child" when the "intelligence's" took him to their UFO base.

He also denied seeing a magazine in which a UFO abduction story, very like Fontaine's, was being serialised. Yet Control established that this very magazine was in Prevost' s flat at the time of the Cergy-Pontoise abduction. The events of the night before the abduction became more confused the more they were investigated. Control discovered that there were five people not three in Prevost's flat that night. Why had the published accounts almost completely failed to mention the presence of Corinne, Prevost's girlfriend and Fabrice Joly? One reason suggested itself: knowledge of the presence of the fourth young man, Joly, might throw doubt on one of the facts most favourable to Prevost and N'Diaye. They had claimed that they had gone straight to the police when Fontaine vanished from their car, even though they knew they might get into trouble because they were driving without a licence. But Joly was there because he had a valid licence and had agreed to drive the three friends to the market at Gisors.

Why were Corinne and Joly never questioned about what happened? Did they see and hear nothing? They could certainly have straightened out some of the contradictions, for Fontaine, Prevost and N'Diaye could not even agree on who had been at the flat on the night before the abduction surely one of the most memorable of their lives. First the three had said they spent the night together. Then Prevost recollected that he had watched a television film with friends elsewhere. Other discrepancies force us to ask how far we can trust their account. They said that they were dubious about their car's ability to start and pushed it to get the motor running, then left Fontaine in the car to make sure it didn't stop. Why didn't Joly, the only licensed driver, do this so that Fontaine could lend a hand with loading the jeans for the market? Did they really sit outside the block of flats at 4 a.m. with the motor running without any complaint from the neighbours? None of the other residents seem even to have heard the sound. What about N'Diaye's completely opposing statement that they loaded the car first and only then started the motor? Whom should we believe?

The account of the one neighbour who did witness anything only makes matters more confused. Returning home at the time the young men were supposedly loading the car, he said he saw two people get into the Taunus estate car and drive away. Yet the three involved said that Fontaine was alone when he drove up onto the road to get a better view of the UFO they had spotted.

Even though UFO's are notoriously difficult to describe, the three accounts of the one at Cergy-Pontoise are particularly far apart. One saw "a huge beam", another "a ball", the third "a flash". One said it was moving fairly slowly, taking two minutes to cross the sky; the others said it was moving fast, gone in a matter of seconds. There was further disagreement about the direction in which it was moving.

The circumstances of Fontaine's return a week after his supposed abduction are no less confused as several stories emerged. One of the journalists covering the case was Iris Billon-Duplan, who worked for a local newspaper and lived close by. Apart from the special interest of a case that had occurred almost on her doorstep, the fact that she lived nearby meant she could follow it personally. As a result, she became closely involved with the witnesses. Indeed, she spent the night before Fontaine's return with Prevost, preparing a definitive account of thecase.

According to the journalist's published account, N'Diaye went off to bed shortly after midnight, leaving her with Prevost. He told her that he had no food or money because his involvement in the UFO affair was keeping him from working. So she suggested that they go to her flat where she could give him a meal while they continued to work on the article. This explains why Fontaine did not find Prevost in when he returned and went to Prevost's flat. We know that Fontaine then went to N'Diaye's flat and succeeded in rousing him. But according to the journalist's account, N'Diaye then left Fontaine and hurried round to her flat to tell her and Prevost the news. Should we believe Iris Billon-Duplan or Salomon N'Diaye? For his statement, made to the police, flatly contradicts hers.

His story was that he happened to wake up at about 4.30 a.m., looked out of his window and saw a ball of light on the main road. When he saw a silhouetted figure emerge from it, he recognised his friend Franck Fontaine. He then hurried to a telephone to report the return to Radio Luxembourg, believing he would get a reward for information about Fontaine's whereabouts. (In this he was mistaken; it was Europe Numero I that had offered a reward.)

Radio Luxembourg later confirmed that such a call had been made, but not at 4.30 a.m. because there was nobody on duty at that hour. The implication is that N'Diaye telephoned later than 4.30 a.m. and that he waited to inform the police until he had attempted to claim the reward money not saying much for his concern about his friend. In the event, it was Radio Luxembourg staff who told the police that Franck Fontaine had returned. According to them, they had received an anonymous call from a man who, just as he was going to work, saw Fontaine coming back. Surely N'Diaye would not have made an anonymous call if he wanted to collect the reward.

These contradictions are just a sample from Control's 50-page report. There is confusion, if not outright deception, at every stage of the affair. Some of the discrepancies can be attributed to faulty memory, but such an explanation can hardly be stretched to account for Prevost's extraordinary visit to the tunnel. As a case history, Cergy-Pontoise is so ambiguous that few will be ready to give it serious credence. Yet it caused such a sensation that it is still worth asking what really happened. If the abduction was not genuine, was it a put-up job from the outset? Or did the witnesses gradually distort what was fundamentally a true UFO experience? If so, at what point did deceit and contrivance begin? There are several ways to answer these questions. We may believe that Franck Fontaine was abducted as claimed, that all the witnesses were doing their best to tell the truth and that contradictions crept in because of defective memory. However, the extent of the discrepancies makes it easier to believe that the trio elaborated the story for their own purposes, adding sensational details that they may or may not have believed actually happened.

Alternatively, we may surmise that Franck Fontaine was not in fact abducted, but that he sincerely believed he was. He may have been in, or put into, some altered state of consciousness in which he experienced the illusion of the abduction. That this can happen is an established psychological phenomenon, so we cannot rule it out altogether. But it does raise questions about Fontaine's two friends. If he was deluded, where do they stand? Were they also in an altered state of consciousness, experiencing or being made to believe in the same illusion? And does this explain the contradictions? If so, who fed them the illusion and made them believe in its reality?

While neither of these explanations can be ruled out entirely, we may consider it most plausible that the whole affair was a fabrication from the start that there never was any abduction and that the three young men put the story together for fun, for gain or for some undiscovered ideological motive. We know that the trio immediately co-operated with Jimmy Guieu in a commercial enterprise. We learn from Control that Prevost, clearly the dominant one of the three, was noted for practical joking at school. Indeed he told the Control investigators, "You bet I'm a clown!"

The reports are consistent with the hypothesis that Prevost persuaded his two companions to stage a hoax, but that Corinne and Fabrice Joly refused to go along. Perhaps none of them expected their story to attract so much attention and they were forced to improvise beyond their prepared narrative. This could explain such muddles as the contradictory accounts of Fontaine's return.

Another question then arises: was Guieu a party to the deception? Did he suspect the story from the start but, as a professional writer, recognise its money-making potential? Did he start by believing them, as he claimed to do, then discover the hoax but decide to go along with it perhaps because he was already committed? Or did he believe that the affair was genuine? The last supposition seems unlikely in the light of Guieu's long involvement with UFOlogy, unless he was unusually gullible. On the other hand, it is hard to believe that he would risk his reputation by endorsing a case that he knew to be a fake. We are probably left with the surmise that he discovered a hoax but decided not to reveal it for reasons of his own.

If the Cergy-Pontoise contact was indeed all a hoax, it would explain why the trio committed themselves to the uncritical Guieu and his Institut Mondial des Sciences Avances (World I Institute of Advanced Sciences). IMSA has little following or reputation, but Guieu offered the backing of a big name, sympathetic support and the chance to make a substantial profit from a book bearing his name. And other UFO organisations might have uncovered the deceit in a short time, if deceit it was.

In the absence of any definite proof, all this is merely speculative. Will the truth ever be established? There are hopes that it may be. During their researches, Control came across a tantalising clue that they were unable to follow up. It seems that during Fontaine's disappearance, a school in Cergy-Pontoise was working on a project about it with the local newspaper the one that was later to carry Iris Billon-Duplan's version of Fontaine's return. Some of the children learned that one of the school workers was an aunt of Fontaine and interviewed her as part of their project in the presence of one of the teachers and one of Iris Billon-Duplan's colleagues from the paper.

During the interview, Fontaine's aunt said angrily that she knew perfectly well where her nephew was. He was, she said, staying with a friend.

Was she stating a fact or simply saying what she thought to be true? Who was the friend and where did he or she live? The answers to these questions could settle the Cergy-Pontoise mystery. But until we learn if someone knew where Fontaine was all the time, the case must remain open.