The purpose of this book is to explore some of those great mysteries of the earth that have captured the popular imagination, and especially those having their roots in our specialties of archaeology and geology. The average reader probably is unfamiliar with the earth sciences or the archaeological history of man. Nor does the average reader have the time and literary resources to verify all he or she reads. Our aim is to lend a helping hand by examining the evidence that surrounds such mysteries as the legend of Atlantis and the ruins of Stonehenge, and, as logically as we can, sift truth from falsehood and exagger- ation. Early man found himself in a world of unimaginable mysteries: meteors streaking across a star-studded sky, the darkness beyond the campfire's glow, the sound and fury of a volcano's eruption. Our earliest ancestors were probably mysteries to themselves, and totally susceptible to the subjectivity of their world. Fantasies may have been as much a formative influence as toolmaking in the early development of culture. As human beings gathered knowledge and understanding of their surroundings, old mysteries vanished, only to be replaced by others because so much was not understood.