Unidentified flying objects (UFOs), or flying saucers as they are known to many persons, have been the subject of considerable interest on the part of the public as well as the U.S. Air Force for two decades. On Dec. 30, 1947, the Air Force was given the responsibility by the Department of Defense for investigating UFO sightings. This booklet is intended to meet the needs of individuals seeking information about UFOs. The introduction is a brief history of UFO reports and studies and provides some information on scientific observations and analyses. The section "aids to identification of flying objects" is more technical and should be of interest to persons desiring in-depth information on flying objects and natural phenomena. The "questions and answers" section will help answer many of the questions commonly asked about UFOs.