What American general was convinced the UFO's are spaceships from other worlds? Have USAF jet-fighters ever fought with flying saucers? Was the Maury Island Mystery a hoax? Did flying saucers ever really buzz the White House? Are there authentic photos of UFO's? What is the true story behind the Lubbock Lights? Here are the facts: More than 20 percent of all sightings are classified as "Unknowns." These are objects seen in our skies that cannot be identified as balloons, man-made aircraft or meteors, and that cannot be attributed to weather or atmospheric illusions. Neither can they be explained away as hoaxes or hallucinations. If they are none of these, then what are UFOs? In this meticulously documented book, Edward J. Ruppelt, former head of the United States Air Force project investigating flying saucers, gives first-hand quotes of the opinions of the top military brass, the most eminent scientists, and hundreds of reputable pilots. Study their comments carefully—the answers they come up with may well determine humanity's future.