The United States Air Force managed three UFO projects, from 1948 to 1969. The first was Project Sign, the second Project Grudge, and the third, longest lasting, and most widely recognized, Project Blue Book.
Project Blue Book produced several lengthy reports, from No. 1 to No. 14, with Project Blue Book Special Report No. 14 being the most important for UFO research, as it contained the study by Battelle Memorial Institute that analyzed the characteristics of UFOs in sightings that were unidentified. Leon Davidson was one of the earliest scientists to become interested in UFOs. Among other projects, he reprinted Special Report No. 14 with additional documents, notes and commentary. The copy of the publication linked below is Dr. J. Allen Hynek’s personal copy, with his annotations.
Researcher Brad Sparks has compiled a comprehensive catalog of 2,200 UFO cases that the US Air Force has labeled “Unknown,” supplemented with other data supplied by other researchers for the time period January 1947–March 1969. Sparks gives a good explanation in the document of the difficulty in establishing an official compendium of Project Blue Book cases, because many have disappeared from the officially released files. He also provides a list of operational dates of Air Force UFO projects, the names of divisions involved in data collection and evaluation, and a list of the chiefs of UFO projects at Wright-Patterson Air Force Base.
Project Blue Book case files can be accessed online through the Fold3 website. Cases are browsable by year or searchable by person, place, date, keyword, record, and service number. Each case file relates to one sighting or to a group of closely related sightings. The files contain reports from UFO observers, correspondence between these observers and the Air Force, newspaper and magazine clippings, and reports of analyses of photographs and physical evidence. Some reports were submitted by letter or telegram, but most reports of sightings were submitted on an Air Force questionnaire which contains the name and address of the observer, the date and hour of the sighting, and a description of what the observer saw. Each case file contains a control sheet which summarizes the sighting report and shows the Air Force explanation and conclusions for the sighting. Access to Blue Book records is through 94 rolls of 34mm microfilm in the US National Archives Reading Room. Many of the witness names have been redacted, even though they have been published elsewhere in the UFO literature.
Jennie Zeidman was a student of J. Allen Hynek at Ohio State when he asked her to assist with this consulting work on Project Blue Book, after he was brought back as an Air Force UFO consultant by Capt. Edward Ruppelt. Their work was done under Project Stork and Project Henry. In this IUR article Jennie provides a glimpse into what the work was like for Hynek and her in 1953, a pivotal year for the project, evaluating UFO sightings and completing other tasks assigned by Blue Book.