The principles of quantum mechanics are the basis of everything in the physical world--from atoms to stars, from nuclei to lasers. Quantum paradoxes and the eventful life of Schroedingers Cat are explained, along with the Many Universe explanation of quantum measurement in this newly revised edition. Updated throughout, the book also looks ahead to the nanotechnology revolution and describes quantum cryptography, computing and teleportation. Including an account of quantum mechanics and science fiction, this accessible book is geared to the general reader. Anthony Hey teaches at the University of Southampton, UK, and is the co-author of several books, including two with Patrick Walters, The Quantum Universe (Cambridge, 1987), and Einsteins Mirror (Cambridge , 1997). Patrick Walters is a Lecturer in Continuing Education at the University of Wales at Swansea. He co-ordinates the Physical Science Programme in DACE which includes the Astronomy Programme. His research interests include science education, and he also writes non-technical books on science for the general reader and beginning undergraduates.