In this book Alexander Kondratov takes a look at some of the blank spaces in manâs knowledge that can be filled in by further evidence obtained from underwater archeology. In the Pacific Ocean these include such riddles as the culture of Easter Island, the origin of the American Indians, the original homeland of the Polynesians and the peopling of Australia. In the Indian Ocean one of the mysteries is how the ancient Dravidian civilisation spread. Among the secrets of the Atlantic are the warm and cold legendary islands of St. Brendan, Antilia and Thule, the extinct tribes of the Canary Islands, and Atlantis, a fascinating mystery that has given rise to a voluminous body of literature. The author sets forth the main hypotheses that have been advanced to solve these riddles and analyses them from the standpoints of ethnography, linguistics, geology and other sciences. But he does not try to impose any of the hypotheses on the reader. The conclusions he draws are extremely cautious, and in cases where there is insufficient data the question is left open. This highly interesting book is intended for the general reader. Indeed, no educated person can fail to take an interest in problems that have a direct bearing on the human race.