This work explores encounters between people, including fighter pilots, and UFOs. The author states that while Earth has been visited by aliens for centuries, the Air Force was investigating these cases and hiding them. He researched sightings and concluded the saucers were interplanetary. He had some access to original military files but didn't believe in space visitors before starting this book... One of the very first big books in ufology! Fascinating and spellbinding, filled with expertise and information.