This groundbreaking book explores the fascinating psychology behind public beliefs in extraterrestrial visitors and UFOs (unidentified flying objects, now often termed Unidentified Aerial Phenomena). Drawing on extensive opinion poll and academic research data from around the world, Barrie Gunter delves into the complex psychological processes that shape our interpretations of ambiguous experiences. The analysis reveals how psychological factors profoundly influence our beliefs about extraterrestrial life. The book explores how an individual's religious and paranormal beliefs, internalised cultural narratives, personality characteristics, and cognitive biases create frameworks through which they process and recall unexplained phenomena. The book also investigates how these psychological predispositions affect responses to government secrecy, potentially fuelling conspiracy theories about extraterrestrial activity. Neither dismissing unexplainable occurrences as bogus nor accepting them at face value, this nuanced exploration illuminates the crucial role of social and cognitive psychology in understanding why certain beliefs take hold. It fills a significant gap in current literature, offering valuable insights for students and scholars of cognitive, social, and para-psychology interested in the psychological underpinnings of extraterrestrial beliefs.