Do you believe in the possibility that life exists elsewhere in the universe? Have you seen something in the night sky that can t be attributed to atmospheric anomalies, man-made aircraft, optical illusions, or other natural phenomena? Are you ready to weigh hard evidence against hoaxes & fact against fiction? This volume is the essential reference for UFO investigators -- a serious & practical guide to exploring the mysteries of alleged alien activity. This book more than 240 full-color photos & illustrations; a sighting report form & examples of 21 standard UFO types; & practical advice & contact information for your investigation, including lists of major UFO groups, conferences, government sources, & more.