The Big Bang theory--the leading explanation for the origin of the universe--posits that space and time sprang into being about 14 billion years ago in a hot, expanding fireball of nearly infinite density. Over the last three decades, the theory has repeatedly had to be revised to address such issues as how galaxies and stars first formed and why the expansion of the universe is speeding up--let alone what caused the Big Bang in the first place. This book presents a bold new cosmology: Steinhardt and Turok recount remarkable developments in astronomy, particle physics, and superstring theory that together form the basis of their groundbreaking "Cyclic Universe" theory. According to this picture, the Big Bang was not the beginning of time, but the bridge to a past filled with endlessly repeating cycles, each accompanied by the creation of new matter and the formation of new galaxies, stars, and planets.--From publisher description.