A young man's spiritual journey. A controversial bestseller. And a scientific theory that threatened to change the world. Just what are the facts behind Erich von Daniken and Ancient Astronaut theory? For more than 40 years, his books have sold over 65 million copies worldwide. He is a hero to some, and a heretic to others--but Erich von Daniken's controversial theories have captured the attention of the world and ignited a movement known as Ancient Astronaut Theory. His exhaustive search for the truth about mankind's otherworldly origins have started to gain acceptance with a small but growing number of Ancient Astronaut theorists--men and women who have expanded, and at times refined, von Daniken's findings. Did ancient astronauts really come to planet Earth? And, if so, what was their purpose? And perhaps even more important--will they come again?