Recent developments in cosmology and particle physics, such as the string landscape picture, have led to the remarkable realization that our universe - rather than being unique - could be just one of many universes. The multiverse proposal helps to explain the origin of the universe and some of its observational features. Since the physical constants can be different in other universes, the fine-tunings which appear necessary for the emergence of life may also be explained. Nevertheless, many physicists remain uncomfortable with the multiverse proposal, since it is highly speculative and perhaps untestable. In this volume, a number of active and eminent researchers in the field - mainly cosmologists and particle physicists but also some philosophers - address these issues and describe recent developments. The articles represent the full spectrum of views, providing for the first time an overview of the subject. They are written at different academic levels, engaging lay-readers and researchers alike.
'... probably the most comprehensive tome on the subject around at the moment and, like the others, I imagine it will have a long shelf-life ... this well-constructed collection of writings is the best we can possibly hope for in the era of this new great debate.' Pedro Ferreira, Physics World 'This book really does lie at the frontier of cosmology, philosophy and possibly even theology. It is essential reading for anyone who wants to consider these ideas in depth.' Martin Redfern, Science, People and Politics 'Reading this book is a complex and rich experience. I find it useful as recommended reading as an introduction for undergraduate students.' Luca Valenziano, CERN Courier '... an essential acquisition for those requiring an up to date account of the various physical proposals and their problems.' Science and Christian Belief