Edward U. Condon

From 1948 to 1969, the U.S. Air Force conducted official investigations of UFO reports. Project Sign, followed by Project Grudge, and finally Project Blue Book collected nearly thirteen thousand reports from civilian and military witnesses in the United States and elsewhere and attempted to determine whether any were based on actual extraterrestrial sightings. The air force attributed more than 95 percent of the cases to normal causes, such as weather, misperceptions of the moon and planets, and misperceptions of ordinary aircraft. The remaining seven hundred were classified as unexplained.

Both public and military dissatisfaction with the air force role in the UFO investigations led to the establishment in November 1966 of an independent but government—funded study that, it was hoped, would shed some unquestionable and objective light on the UFO question. The University of Colorado agreed to host the...