Contemporary theories on the origin of the phenomenon, with chapters on man-made UFOs; UFO psychology and abductions; UFO cover-ups and crop circles; unidentified submarine objects; psychic UFOs; demonic UFOs; extra-terrestrial intelligence and humanoids. Contributors: W.A. Harbinson; Alvin Lawson; William H. Spaulding; Peter Brookesmith; Janet and Colin Bord; Jenny Randles; Hilary Evans; Ron Hyams; Charles Bowen. With colour and black and white photographs and artwork.