Book excerpt: Unlike current survey articles and textbooks, here the so-called confluence and termination hierarchies play a key role. Throughout, the relationships between the properties in the hierarchies are reviewed, and it is shown that for every implication X => Y in the hierarchies, the property X is undecidable for all term rewriting systems satisfying Y. Topics covered include: the newest techniques for proving termination of rewrite systems; a comprehensive chapter on conditional term rewriting systems; a state-of-the-art survey of modularity in term rewriting, and a uniform framework for term and graph rewriting, as well as the first result on conditional graph rewriting.