Einstein's general theory of relativity is perhaps the most important perspective to emerge in a century of astonishing progress in the field of physics. However, it is also a notoriously difficult subject for beginning students. This book describes general relativity in terms understandable to undergraduates in physics and astronomy. It discusses concepts and experimental results, and provides a succinct account of formalism. A brief review of special relativity is followed by a discussion of the equivalence principle and its implications. Other topics covered include concepts of curvature and the Schwarzschild metric, tests of the theory of relativity, black holes and their properties, gravitational radiation and methods for its detection, the impact of general relativity on cosmology, and the continuing search for a quantum theory of gravity. A set of worked examples, background appendices, and an annotated bibliography are also included. Written at a level accessible to nonspecialists, this book is especially strong on the experimental physics of relativity.