Dr. Hynek, who has studied the question more thoroughly than any other distinguished scientist, has conveniently divided UFO phenomena into six general categories. The first, “Nocturnal Lights,” is the one most commonly reported and the least strange of all. Most such reports are easily explained as heavenly bodies, meteors, etc. and are not considered UFOs. Truly puzzling Nocturnal Lights (those that remain unidentified), which seem to display intelligent action but are not explainable as ordinary aircraft, are often seen by multiple witnesses, including police officers, airplane pilots, and airport tower operators.

The second category of UFOs is “Daylight Discs,” whose behavior is close to that of Nocturnal Lights. These are the original “flying saucers,” and in fact almost all of the unidentified sightings in this category are of discs which vary in shape from circular to cigar-shaped. They are often metallic in appearance, and are reported as capable of extremely rapid starts and stops and high speed, as well as maneuvers (such as sudden reversals of direction and motionless hovering) that are beyond the capacity of any present aircraft. There are many purported photographs of such discs, but none of them is very convincing owing to the distance involved and the possibility of trick photography. Like Nocturnal Lights, UFOs in this category are almost always reported as being totally noiseless, and sometimes two or more of them are seen.

The third category is that of “Radar-Visual” reports – that is, radar sightings that are confirmed by independent visual observation (radar by itself being subject to various kinds of misperceptions). Most of these cases occur at night, and the best cases involve simultaneous sightings by airplanes (sometimes purposely dispatched to follow the UFO) at fairly close range; in these cases the UFO always outmaneuvers the airplane, sometimes following it, and finally disappears in a burst of speed (up to 4000 miles and more per hour). Sometimes, as in categories 1 and 2 also, the object seems to divide and become two or more distinct objects; and sometimes clear visual sightings of such objects by pilots in the air are not picked up by radar at all. Sightings in this category, just as in the first two, last from between a few minutes to several hours.

A number of cases in the first three categories are well documented, with numerous reliable, experienced, and independent witnesses. Still, any one case, as Dr. Hynek notes, might be caused by some extremely unusual set of circumstances and not by some new and totally unknown phenomenon. But when many well-documented cases, all similar to each other, accumulate, the chance that they are all unusual misperceptions of familiar objects becomes very small. This is why serious UFO investigators are now concentrating on the collection of a number of well-documented cases, and the comparison of numbers of reliable testimonies already begins to show definite patterns of UFO activity.

The emotional response of those who have witnessed UFOs of the first three categories is one of simple perplexity and puzzlement; they have seen something whose behavior seems totally inexplicable, and they are left with a tantalizing desire to see it “just a little closer.” Only in a few cases – generally involving pilots who have tried to pursue the unidentified objects – has something like real fear been experienced at the encounters with something that seemed intelligently directed and possessing a technology in advance of anything known today. In cases involving “Close Encounters,” on the other hand, the human response becomes much deeper and the psychic side of the phenomena more pronounced.

“Close Encounters of the First Kind” (CE-1) are sightings of a luminous object at close range (about 500 feet or less), the light being sometimes very bright and casting luminescence on the ground below. When the shape of the object is described, it is generally stated to be oval, sometimes with a dome on top, and the lights are often described as rotating, usually in a counterclockwise direction. The objects often hover close to the ground, without sound or (occasionally) with a humming sound, sometimes moving close to the ground over considerable distances, and eventually taking off extremely rapidly, soundlessly, and usually straight up. There are numerous multiple-witness accounts of such “Close Encounters”; these accounts are invariably quite similar to each other, as though it is indeed one and the same object (or similar objects) that is being observed in all well-documented cases. Typically, these cases occur at night in sparsely settled area and there are a small number of witnesses for each sighting (an average of three to four in the cases examined by Dr. Hynek).

“Close Encounters of the First Kind” are always awesome and often frightening, but leave no visible marks; witnesses are usually so overwhelmed by the experience that they neglect to take photographs of the object even when a camera is nearby. Typical of the effect on witnesses is this comment in a 1955 UFO report: “I can assure you, once anyone has seen an object such as this so closely and for a period of even one minute, it would be etched in their memory for all time.” The experience is so unusual that witnesses are often not believed when they report it – a fact that causes many to report it only confidentially, after many years, or not at all. The experience is intensely real to those who experience it – but largely unbelievable to others.

A typical “Close Encounter of the First Kind” involved two Portage County, Ohio, deputy sheriffs in 1966. About 5 a.m. on the morning of April 16, after stopping to investigate a parked car on a country road, they saw an object “as big as a house” ascending to tree-top level (about 100 feet). As it approached the deputies it became increasingly bright, illuminating the area all around, then stopped and hovered over them with a humming sound. When it moved away they pursued it for some 70 miles into Pennsylvania, at speeds of up to 105 miles per hour. Two other police officers saw the object clearly at a higher elevation before it went straight up and disappeared about dawn. Congressional pressure forced “Project Blue Book” to investigate this case; it was “explained” as an “observation of Venus,” and the officers who saw it were subjected to considerable ridicule in the press, leading to the breakup of one officer’s family and the ruin of his health and career. Personal tragedies of this kind among people who have “Close Encounters” with UFOs are so common that they should definitely be included in the typical characteristics of this phenomenon.

“Close Encounters of the Second Kind” (CE-II) are essentially similar to CE-1 experiences, with the one difference that they leave some striking physical and/or psychological effects of their presence. These effects include marks on the ground, the scorching or blighting of plants and trees, interference with electrical circuits causing radio static and the stoppage of automobile engines, discomfort to animals as evidenced by strange behavior, and effects on humans which include temporary paralysis or numbness, a feeling of heat, nausea, or other discomfort, temporary weightlessness (sometimes causing levitation), sudden healings of sores and pains, and various psychological and physical after-effects, including strange marks on the body. This kind of UFO encounter gives the greatest possibility for scientific investigation, since in addition to human testimony there is physical evidence that can be examined; but little investigation has actually been undertaken, both because most scientists are afraid to get involved in the whole question of UFOs, and because the evidence itself is usually inconclusive or partially subjective. One catalog has been compiled of over 800 cases of this type in 24 countries. No actual “piece” of a UFO has ever been authenticated, however, and the markings left on the ground are often as baffling as the sightings themselves. The most frequent marking left on the ground after a sighting (the UFO itself having been seen either on the ground or just above it) is a burned, dehydrated, or depressed area in the shape of a ring, usually 20 to 30 feet in diameter and 1 to 3 feet thick; these “rings” persist for weeks or months and the interior of the ring (and sometimes the whole circle) is reported to be barren for a season or two after the sighting. A few chemical analyses of the soil in such rings have produced no definite conclusions as to the possible origin of this condition.

“Close Encounters of the Second Kind” often happen to persons during the night in isolated sections of road. In many similar cases a glowing object lands in a field nearby or on the road in front of an automobile or truck, the engine and headlights on the automobile fail, and the occupants become terrified until the UFO leaves, often shooting suddenly straight up without a sound; the engine of the vehicle then can operate again, and often comes on by itself.

The strangest of all UFO reports are those that deal with “Close Encounters of the Third Kind” (CE-III) – that is, UFO experiences involving “animated beings” (“occupants” or “humanoids”). The first thought of many people when hearing of such reports is to picture “little green men” and dismiss the whole phenomenon as unbelievable – a hoax or hallucination. However, the success of the recent American science-fiction film, named precisely for this category of UFO phenomena Close Encounters of the Third Kind (for which Dr. Hynek served as technical consultant), together with evidence of the Gallop Poll in 1974 that 54% of those who are aware of UFOs believe that they are real, and 46% of all those interviewed believe in intelligent life on other planets (the percentage today would certainly be greater) – point to the rapidly increasing acceptance by contemporary men of the possibility of actual encounters with “non-human” intelligences. Science fiction has given the images, evolution has produced the philosophy, and the technology of the space age has supplied the plausibility for such encounters.

Astonishingly, these encounters seem actually to be occurring today, as attested to by the evidence of many believable witnesses. Of crucial importance, therefore, is the interpretation that must be made of these occurrences; is the reality behind them an actual contact with “visitors from outer space,” or is this only an explanation provided by the spirit of the times for a contact of a different kind altogether? As we shall see below, today’s scientific investigators of UFOs have already asked these questions.

Dr. Hynek admits his own repugnance to face the possibility of CE-III experiences: “To be frank, I would gladly omit this part if I could without offense to scientific integrity.” However, since his aim is scientific objectivity, he finds it impossible to ignore the well-documented cases, from believable witnesses, of this strange phenomenon. Of nearly 1250 “Close Encounters” reported in a catalog by Dr. Jacques Vallee, 750 report the landing of a craft, and more than 300 of these report “humanoids” in or about the craft; one-third of all these are multiple-witness cases.

In one “humanoid” case, which occurred in November 1961, in one of the northern plains’ states in the USA, four men were returning from a hunting trip late at night, when one of the men noticed a flaming object coming down, as if it were an airplane crashing about a half mile up the road from them. When they reached the site of the “crash,” all four men saw a silo-shaped craft in a field, sticking in the ground at an angle, with four seemingly human figures standing around it (this was at a distance of about 150 yards). They flashed a light on one of the figures, who was about four-and-a-half feet high and wearing what looked like white coveralls; he made a gesture to the men to stay back. After some hesitation (still thinking it was a plane crash), they went to a nearby town for a police officer, and when they returned they saw only some small red lights, something like automobile lights. They drove into the field with the officer and followed the lights, only to discover that they suddenly disappeared, leaving no tracks whatsoever, despite the muddiness of the field. After the puzzled police officer left, the men again saw the “silo” coming down out of the sky with a reddish glow. Instantly after the object landed, two figures were visible next to it; a shot was fired (although none of the men admitted to firing it) and one of the figures was “hit” in the shoulder with a thud, and spun around and down to his knees; in panic the men ran to their car and raced off, agreeing among themselves not to mention the incident to anyone. They returned home with a strange feeling that there was some period of time lost during the night. The next day one of the men was visited at his work by several well-groomed official-looking men, who asked him questions about the incident (but without mentioning the shooting) and then took him in their car to his home, where they questioned him about his clothes and boots and then left, telling him not to say anything about the incident to anyone. The hunter assumed these men were United States Air Force investigators trying to conceal some new secret device, but the men never identified themselves and never contacted him again. All four men were extremely shaken up by the incident, and after six years one of them felt compelled to tell the whole story to a U.S. Treasury agent.