"A history of discovery as revealing as the ways of science." The New York Times "Offers the purest intellectual excitement, the pursuit of knowledge for knowledge's sake...." Wall Street Journal "Beautifully illustrated, superbly written, and thoroughly documented." San Francisco Examiner This book presents a history of the idea of continental drift, which revolutionized our understanding of geology. Sullivan presents the idea from its tentative beginnings in the 19th century to the accumulation of overwhelming evidence in the 1960s. The second edition is extensively updated to reflect our current understanding of the basic geophysics underlying continental drift as well as more recent corroborating evidence. The book is written at a slightly more technical level than the average New York Times science news story. Walter Sullivan, as Science Editor of the New York Times, witnessed many of the scientific discoveries described here, having, for example, accompanied four research expeditions to Antarctica.