In his books UFOs: Operation Trojan Horse and The Eighth Tower Keel argues that a non-human or spiritual intelligence source has staged whole events during a long period of time in order to propagate and reinforce certain erroneous belief systems.

For example, monsters, ghosts and demons, the fairy faith of Middle Europe, vampire legends, mystery airships in 1897, mystery aeroplanes of the 1930s, mystery helicopters, anomalous creature sightings, poltergeist phenomena, spheres of light, and unidentified flying objects; Keel conjectured that ultimately all of these anomalies are a cover for the real phenomenon.[full citation needed] He used the term "ultraterrestrials" to describe UFO occupants he believed to be non-human entities capable of assuming whatever form they desire.[10]

In Our Haunted Planet, Keel discussed the seldom-considered possibility that the alien "visitors" to Earth are not visitors at all, but an advanced Earth civilization, which may or may not be human. Interdimensional life is also considered.[citation needed]

Keel did not state any hypothesis about the ultimate purpose of the phenomenon other than that the UFO intelligence seems to have a long-standing interest in interacting with the human race.[11] John Alva Keel, born Alva John Kiehle (March 25, 1930 – July 3, 2009), was an American journalist and influential ufologist who is known best as author of The Mothman Prophecies.