ENDLESS UNIVERSE: Beyond the Big Bang, by Paul Steinhardt and Neil Turok

This 300-page book, published in May 2007, presents what may be the most important new theory in decades of the origin and fate of the Universe.  The authors, both eminent academics - Steinhardt is Albert Einstein Professor of Physics and Astrophysics at Princeton, Turok is Chair of Mathematical Physics at Cambridge - propose a Cyclic Universe model in which our Universe cycles endlessly from a Big Bang, expansion, and acceleration, to convergence with an invisible second Universe, leading to another Big Bang and another cosmic cycle.  

The book is clearly written; the science is explained on a level accessible to general readers willing to stretch their minds to encompass the Cosmos.  The authors narrate the development of their new theory through their personal experiences seeking to understand the Universe as they struggled with the challenges of the prevailing theories.