FROM THE BESTSELLING AUTHOR OF the Elegant Universe and The Fabric of the Cosmos comes his most expansive and accessible book to date - a book that takes on the grandest question: Is ours the only universe? There was a time when 'universe' meant all there is. Everything. Yet, in recent years discoveries in physics and cosmology have led to a number of scientists to conclude that our universe may be one among many. With crystal-clear prose and inspired use of analogy, Brian Greene show how a range of different 'multiverse' proposals emerges form theories developed to explain the most refined observations of both subatomic particles and the dark depths of space: a multiverse in which you have an infinite number of doppelgangers, each reading this sentence in a distance universe; a multiverse comprising a vast ocean of bubble universes, of which ours is but one; a multiverse that endlessly cycles through time, or one that might be hovering millimetres away yet remains invisible; another in which every possibility allowed by quantum physics is brought to life. Or, perhaps strangest of all, a multiverse made purely of mathematics. Greene, one of our foremost physicists and science writers, takes us on a captivating exploration of these parallel worlds and reveals how much of reality's true nature may be deeply hidden within them. And, with his unrivalled ability to make the most challenging material accessible and entertaining, Greene tackles the core question: How can fundamental science progress if great swaths of reality lie beyond our reach? Sparked by Green's trademark wit and precision, The Hidden Reality is at once a far reaching survey of cutting-edge physics and a remarkable journey to the very edge of reality - a journey grounded firmly in science and limited only by our imagination.