The ultimate guide to the history, background and meaning of whether UFOs really exist, plus associated phenomena such as alien abduction, crop circles and cattle mutilations. There is also a comprehensive overview of the many conspiracy theories which surround UFOs and abductions - from the craft as secret Nazi technology to weird CIA plots. Written by a ufologist with many years in the field, this exciting and highly provocative book at times reads like a thriller. What messages do UFOs hold for us and for the future of life on earth?