'A writer of exceptional clarity and charm . . . every chapter opens level after level of previously unimaginable, mind-expanding realities' Oliver Sacks There was a time when 'universe' meant all there is. Everything. Yet, as Brian Greene's extraordinary book shows, ours may be just one universe among many, like endless reflections in a mirror. He takes us on a captivating exploration of parallel worlds - from a multiverse where an infinite number of your doppelgängers are reading this sentence, to vast oceans of bubble universes and even multiverses made of mathematics - showing just how much of reality's true nature may be hidden within them. 'Exciting and rewarding . . . captures and engages the imagination . . . Greene has a gift for elucidating big ideas' The New York Times 'The book serves well as an introduction to the multiverse and will open up many people's eyes' John Gribbin 'Few living writers write so lucidly . . . Greene might be the best intermediary I've found between the sparkling, absolute zero world of mathematics and the warm, clumsy world of human language' Boston Globe