Don Berliner with Marie Galbraith and Antonio Huneeus

Most UFOs have only eyewitnesses to confirm their existence. But scientists often aren't convinced by eyewitnesses alone. So when a rare case comes along in which physical traces are left by a UFO, UFO investigators are ecstatic. An incident near Trans—en—Provence, France, on January 8, 1981, was such a case. Although there was only one eyewitness, the French UFO investigations organization, GEPAN, was on the scene the day after the occurrence. Investigators interviewed the witness, examined the UFO landing site, and took soil samples to be analyzed for irregularities. The tests showed that, indeed, the plants in the area had been changed by whatever had happened on January 8.

Some people call this case the best—investigated of all time. Many consider it to be the most convincing as well.

The...