Of all the big names in UFOlogy in the late 20th Century, Jacques Vallée might be the most interesting. A physicist and computer scientist by training, he believed that there was some form of physical reality behind UFOs, but was reluctant to jump to the conclusion that they were necessarily nuts-and-bolts spacecraft from other worlds. In the late 1960s, his classic Passport To Magonia aired his personal theory that if there was any truth to stories of extraterrestrial visitors at all, they seemed more consistent with visits from other dimensions than from distant space – and that the phenomenon had direct parallels with folkloric encounters with angels, fairies and similar.
1979’s Messengers of Deception came about after Vallée decided to turn his attention from the witnessed aerial phenomena themselves to the people who claim to have witnessed them – and, in particular, those who insist they have met the occupants of interplanetary craft. His initial reason for doing so was a hypothesis that UFOs are a real physical phenomenon which has psychological or neurological effects on witnesses, and so by looking to said witnesses it might be possible to find evidence of this.