Time travel in Newton's universe was inconceivable, but in Einstein's universe it has become a possibility. J. Richard Gott III, a Princeton astrophysicist who is a leading researcher in the field, gives readers a guided tour of the potential of traveling through time. Although scientists such as Stephen Hawking and Kip Thorne have previously considered the topic, the delightfully refreshing — but scrupulously careful — Gott goes light-years beyond them in his exploration of this exciting idea. Gott begins by describing how the finest science fiction about time travel has inspired some of today's top scientific ideas on the subject. He goes on to explain how travel to the future is not only possible but has actually happened (astronauts have aged a bit less than we whose feet have stayed solidly on earth), and he examines whether travel to the past might also be possible, given certain physical conditions. He then offers up his most stunning material: the study of time travel can be used to discover whether the universe could have created itself. Finally, asserting that no book on time travel would be complete without a report from the future, Gott predicts the span of human existence, based on a scientific technique he has developed. His conclusion is humbling but wondrous: just in the short time we have lived so far, consider how much we have already learned about the universe. TIME TRAVEL IN EINSTEIN'S UNIVERSE is a book to read not only for its extraordinary subject matter and scientific brilliance but for its joyful writing.