An extraordinary 95 percent of all Americans have at least heard or read something about UFOs, and 57 percent believe they are real. In late 1993, after being pressured by UFOlogists for the release of information on UFOs, the CIA ordered a review of all Agency files. Using CIA records compiled from that review in 1994, this study traces CIA interest and involvement in the UFO controversy from the late 1940s to 1990. It chronologically examines the Agency's efforts to solve the mystery of UFOs, its programs that had an impact on UFO sightings, and its attempts to conceal CIA involvement in the entire UFO issue. What emerges from this examination is that, while Agency concern over UFOs was substantial until the early 1950s, CIA has since paid only limited and peripheral attention to the phenomena. (Illustrated)