Suitable as a one-semester course in general relativity for senior undergraduate or beginning graduate students, this text clarifies the mathematical aspects of Einstein's general theory of relativity without sacrificing physical understanding. The text begins with an exposition of those aspects of tensor calculus and differential geometry needed for a proper exposition of the subject. The discussion then turns to the spacetime of general relativity and to geodesic motion, comparisons and contrasts with Newton's theory being drawn where appropriate. A brief consideration of the field equations is followed by a discussion of physics in the vicinity of massive objects, including an elementary treatment of black holes. Particular attention is paid to those aspects of the theory that have observational consequences. The book concludes with brief introductory chapters on gravitational radiation and cosmology, and includes an appendix that reviews the special theory of relativity. In preparing this new edition, the authors have made extensive revisions to the original text. In particular, the first three chapters -- covering coordinate systems, tensors and the geometry of curved spaces -- have been completely rewritten to make the material readily accessible to physics students. Many examples, exercises and problems help guide the student through the theory.