This book is part of the "The UFO Files" series, based on my own favorite UFO books. It can be read individually or as part of the entire series. UFO is a fascinating subject that you can study in depth and constantly learn more about. This interesting and fascinating book is based on The Flying Saucers are real by Donald Keyhoe. Keyhoe, who relates here his investigation of the flying saucers, writes with twenty-five years of experience in observing aeronautical developments.