Project Blue Book was one of a sequences of systematic studies of unidentified flying objects (UFOs) carried out by the United States Air Force. Started in 1952, it was the second revival of such a study (the first two of its kind being Projects Sign and Grudge). A termination order was given for the study in December 1969, and all activity under its auspices stopped in January 1970.
Project Blue Book had two goals:
- to decide if UFOs were a risk to national security, and
- to scientifically examine UFO-related data.
The Project Blue Book Archive offers researchers free online access to over 50,000 official US Government documents relating to the UFO phenomenon. A search engine and a range of indices are also offered to modernize access to these documents.