Project Blue Book

Project Blue Book was the United States Air Force's official UFO investigation program, running from 1952 to 1969 and compiling 12,618 case files, of which 701 remained formally unexplained at the project's closure. It succeeded two earlier, shorter-lived USAF efforts, Project Sign (1948) and Project Grudge (1949), and represented the U.S. government's longest sustained institutional UFO study until AARO was established in 2022. J. Allen Hynek served as Blue Book's scientific consultant across its entire run, starting as a skeptic hired to debunk cases and ending as one of the field's most respected researchers, having personally reviewed more raw case material than almost anyone else in ufology's history. Roswell, the Air Force's own most famous case, fell under Blue Book's jurisdiction, as did Levelland and the Washington, D.C. flap. The project closed on the recommendation of the 1968 Condon Report, a University of Colorado study whose negative conclusion the Air Force used to justify ending official investigation entirely — a decision critics still challenge given that roughly 30% of the Condon Report's own case studies remained unexplained by its authors' own analysis. Blue Book's files were later declassified and now form a foundational primary-source archive for researchers on every side of the debate.