Once the stuff of science-fiction novels, black holes, and their even stranger cosmologican counterparts, white holes and wormholes, are now the subject of serious inquiry. Physicists who formerly shunned these astrophysical eccentricities have begun to theorize about them and search for the physical proof of their existence with the zeal of converts. The unavoidable conclusion of this research is that these "rips in the fabric of spacetime" are not only real, they might actually provide a passage to other universes and travel through time. This book tells the story of the theories and discoveries that have led scientists to these conclusions.