When people think about unidentified flying objects (UFOs), they tend to think of flying discs piloted by gray beings with large heads and enormous eyes. They tend to think that these sightings only started relatively recently and that belief in UFOs is some sort of modern religion brought on, perhaps, by the very justifiable fears of a nuclear age. But a study of the phenomenon quickly reveals that humanity has been seeing UFOs since the beginning of recorded history and perhaps a lot longer than that.

The first large-scale, official investigation came during the UFO flap of 1947. On December 30, 1947, Major General L. C. Cragie, director of research and development for the United States Air Force, authorized the study of the flying saucer problem. His statement carried the line "by command of the chief of staff." The program was called Project Sign, and it would be the first of three known U.S. government studies of the UFO phenomenon. Project Sign was the shortest lived of the three studies. The study began on January 22, 1948, and reports were sent that August to Air Force Chief of Staff General Hoyt Vandenberg. The report started that too many sightings by reliable witnesses had occurred for the phenomenon to be a case of mass hysteria or mistaken natural phenomena and that the flying saucers could be visitors from another planet.

Project Grudge was replaced in 1952 with the famous Project Blue Book, which took UFO sightings much more seriously and was actually given the funds to properly investigate some of the more promising sightings. Instead of following Project Grudge's recommendation that "the investigation and study of reports of unidentified flying objects be reduced in scope," this secret study amassed a huge amount of data, and its recommendations would help bring about the formation of the secretive Robertson Panel.