Includes bibliographical references (p. 339-356) and index.
Spacetime and the philosophical challenge of quantum gravity / Jeremy Butterfield and Christopher Isham -- Naive quantum gravity / Steven Weinstein -- Quantum spacetime: what do we know? / Carlo Rovelli -- Reflections on the fate of spacetime / Edward Witten -- A philosopher looks at string theory / Robert Weingard -- Black holes, dumb holes, and entropy / William G. Unruh -- Higher-dimensional algebra and Planck scale physics / John C. Baez -- On general covariance and best matching / Julian B. Barbour -- Pre-Socratic quantum gravity / Gordon Belot and John Earman -- The origin of the spacetime metric: Bell's Lorentzian pedagogy and its significance in general relativity / Harvey R. Brown and Oliver Pooley -- Quantum spacetime without observers: ontological clarity and the conceptual foundations of quantum gravity / Sheldon Goldstein and Stefan Teufel -- On gravity's role in quantum state reduction / Roger Penrose -- Why the quantum must yield to gravity / Joy Christian.