Richard Hall compiled this massive reference work drawing on thirty years of UFO sighting reports, organizing thousands of cases into categories that reveal patterns across time and geography. Hall, who served as assistant director of the National Investigations Committee on Aerial Phenomena, brings the documentary rigor of an archivist to material often dismissed as unworthy of serious attention. The book includes a master chronology of significant sightings, photographic evidence, electromagnetic effects on vehicles and equipment, and cases involving multiple credible witnesses including pilots and military personnel. Hall examines sightings by type: daylight discs, nocturnal lights, radar-visual cases, and close encounters. He reproduces primary documents including military reports and scientific analyses, allowing readers to evaluate evidence directly rather than relying on secondhand summaries. The work functions as both encyclopedia and argument, contending that the volume and consistency of reports warrants systematic study rather than reflexive dismissal. Hall maintained that explaining away individual cases did not account for the phenomenon's persistence across cultures and decades. While making no claims about extraterrestrial origins, he insists that something real and unexplained deserves investigation. The book remains an essential primary source for anyone seeking to understand what witnesses have reported and how investigators have approached this enduring mystery.