What is a black hole? Could we survive a visit to one? Perhaps even venture inside? What would we find? Have we yet discovered any real black holes? And what do black holes teach us about what physicist John Archibald Wheeler called “the deep, happy, mysteries of the universe”? These are just a few of the tantalizing questions examined in this jargon-free review of one of the most fascinating topics in modern science. In search of the answers, we trace a star from its birth to its death throes, take a fabulous hypothetical journey to the border of a black hole and beyond, spend time with some of the world’s leading theoretical physicists and observational astronomers scanning the cosmos for evidence of real black holes, and take a whimsical look at some of the wild ideas black holes have inspired.