Whenever people feel anxious about the future, they turn to prophets and seers for guidance. This book surveys the phenomenon of prophecy over the past 4,000 years and explores the accuracy of past visions as well as the continuity of the prophetic tradition. It contains a number of amazing and curious stories on how the great predictive systems work, including the I Ching, the Mayan prophecies, the Aztec calendar, the Tarot, and West African divination. Special coverage is given to individual prophets and visionaries, including Merlin, the Oracle at Delphi. Nostradamus, John Dee, Sitting Bull, Edgar Cayce, H.G. Wells, etc.