It is now widely accepted that our universe exploded around 15 billion years ago from an unimaginably energetic initial event: the big bang. As the primordial material expanded and cooled, it evolved into the exquisite patterns of stars and galaxies we now observe. The mix of energy and radiation that characterizes our universe was imprinted in that initial instant - as were the binding forces of nuclear physics and gravity that controlled our universe's evolution. The experimental triumphs and theoretical insights of recent years offer the most dramatic enlargement in our concept of the universe since astronomers first realized the sun's true place among the stars. Sir Martin Rees draws these advances together with up-to-the-minute research on black holes, dark matter, and nucleosynthesis of the elements. He also sheds light on some of the personalities behind the science, offering first-hand impressions of Subrahmanyan Chandrasekhar, Stephen Hawking, John Archibald Wheeler, and Fred Hoyle, among others. Professor Rees argues that a family - even an infinity - of universes may have been created, each by its own big bang, and each acquiring a distinctive imprint and its own laws of physics. These baby universes will either live out their immense cosmic cycle, or die because those laws do not allow them to achieve longevity. The multi-universe revolution in cosmological thought limned by Rees casts a piercing light on man's place in the cosmos, and argues that the conditions permitting the evolution of life stand on the razor's edge between a dead universe and one filled with living beings.