This book investigates the historical and scientific validity of reported unidentified flying object sightings to determine their potential origins. The authors, Clare and Gene Gurney, compile a wide array of documented accounts to analyze the phenomenon through a lens of skepticism and scientific inquiry. By examining both anecdotal evidence and official reports, the text seeks to categorize common sightings and provide rational explanations for events often attributed to extraterrestrial activity.

Experts categorize this work as a foundational survey for readers interested in the early history of ufology. Readers frequently note the accessible nature of the prose, which avoids overly technical jargon while maintaining a focus on objective analysis.