Term rewriting systems, which developed out of mathematical logic, consist of sequences of discrete steps where one term is replaced with another. Their many applications range from automatic theorem proving systems to computer algebra. This book begins with several examples, followed by a chapter on basic notions that provides a foundation for the rest of the work. First-order and higher-order theories are presented, with much of the latter material appearing for the first time in book form. Subjects treated include orthogonality, termination, lambda calculus and term graph rewriting. There is also a chapter detailing the required mathematical background.