Quantum Gravity: Third Edition (International Series of Monographs on Physics)
Review from previous edition:  "This book maintains a high level of clarity throughout, and is written with admirable patience. It will be found very useful by a beginning researcher in quantum gravity who wants to have a comprehensive overview of the subject. Equally well, senior researchers in the field will find it a handy reference for standard analyses of various aspects of the subject."     --General Relativity and Gravitation"A clear exposition of the fundamental concepts of gravity... an extensive review of the subject."           --Journal of Classical and Quantum Gravity"Suitable for the expert who wants an overview of the state-of-the-art, as well as the novice looking for an introduction to one of the most spellbinding subjects in theoretical physics today."    --Physik-Journal