J. Allen Hynek was an American astronomer and professor, best known for his work in the field of unidentified flying objects (UFOs). He initially served as a scientific consultant for the U.S. Air Force's Project Blue Book, which investigated UFO sightings from 1952 to 1969. Over time, Hynek shifted from skepticism to a more open-minded approach regarding the phenomenon. Hynek developed the Hynek Classification System, which categorized UFO sightings into three main types: Nocturnal Lights, Daylight Discs, and Close Encounters. His research and writings contributed significantly to the public's interest in UFOs and helped shape the modern understanding of the subject.