The classic UFO-shaped like a flying saucer with a dome on top--in reality represents but a small fraction of the mystery aerial objects people have reported seeing over the past half century or so. Eyewitnesses around the world actually describe a bewildering array of forms in flight.

Here, for the first time, is a comprehensive look at the physical structure of UFOs, a book devoted to identifying and categorizing the dozens of different shapes the UFO phenomenon exhibits globally. From double-ringed to triange-shaped UFOs, from saucers to cigar-shaped craft-and more-this book...