Charles Berlitz and William L. Moore

In 1980, a slim little book called The Roswell Incident claimed to tell the story of "the most important UFO encounter in our century." It reported on an incident that had supposedly occurred in July 1947 near Roswell, New Mexico. The authors interviewed witnesses who said that more than thirty years before, they had seen a crashed alien spacecraft, found debris "not of this earth," and even seen the bodies of small, alien beings being carted away by U.S. military authorities, never to be seen again. The book caused something of a sensation, but was only the first in a continuing series of books devoted to investigation of and debate about the Roswell incident.

There's no question that something happened near Roswell at that time, but the question of what it was is still...