While Scully appears to have been duped, there are suggestions that his book might have served as disinformation -- or possibly as an attempt to acclimate the public to the ideas of downed UFOs and alien occupants in case of an unforeseen need for disclosure (such as the crash of a UFO in or near a major city).
Once one allows for the possibility that the Roswell incident involved a nonhuman craft, the idea isn't nearly as paranoid as it might seem.
Note the reference to saucers constricted of an "extremely light, almost impenetrable metal alloy that we have not been able to duplicate." If that sounds familiar, it should. In a videotaped interview, Brig. Gen. Arthur Exon discussed his limited knowledge of the Roswell debris, which was flown to Wright Field (later Wright-Patterson Air Force Base) for inspection in 1947. Echoing descriptions offered by witnesses in Roswell, Exon emphasized his understanding that the Roswell material was remarkably lightweight and durable, consistent with an extraterrestrial interpretation.
Could Scully (or his sources) have arrived at the same description independently? It's not impossible, although I find the parallels conspicuous. Some skeptics might even suggest that Exon's testimony was colored by exposure to Scully's book or "flying saucer" movies that expound on the characteristics of alien metals. In "Earth vs. the Flying Saucers," for example, scientists examining an alien helmet take pains to note its light weight and unusual strength.
Of course, the pointed description in "Earth vs. the Flying Saucers" could have been part of the same hypothetical "contingency plan" responsible for Scully's book. In "Architects of the Underworld" (a wonderfully offbeat ET/conspiracy romp) Bruce Rux argues that "The Thing," an enduring genre favorite, unfolds in a tellingly Roswell-esque manner, from the sudden acquisition of a crashed saucer to the threat posed by a human-like alien presence.
Have works of fiction been seeded with "insider" knowledge as part of a far-reaching effort to educate a complacent public? Or has our own postwar fiction somehow guided the action and appearance of a nonhuman intelligence quite beyond our perceptual vocabulary?