Amazon.com (ISBN 0691050848, Paperback)

Who doesn't love a good argument? When physics heavyweights Stephen W. Hawking and Roger Penrose delivered three sets of back-and-forth lectures capped by a final debate at Cambridge's Isaac Newton Institute, the course of modern cosmological thinking was at stake. As it happens, The Nature of Space and Time, which collects these remarks, suggests that little has changed from the days when Einstein challenged Bohr by refusing to believe that God plays dice. The math is more abstruse, the arguments more refined, but the argument still hinges on whether our physical theories should be expected to model reality or merely predict measurements.

Hawking, clever and playful as usual, sides with Bohr and the Copenhagen interpretation and builds a strong case for quantum gravity. Penrose, inevitably a bit dry in comparison, shares Einstein's horror at such intuition-blasting thought experiments as Schrödinger's long-suffering cat--and scores just as many points for general relativity. The math is tough going for lay readers, but a few leaps of faith will carry them through to some deeply thought-provoking rhetoric. Though no questions find final answers in The Nature of Space and Time, the quality of discourse should be enough to satisfy the scientifically curious. --Rob Lightner