This text provides a balanced introduction to the principles and techniques of heterogeneous catalysis. Beginning with the basic chemistry and physics of catalysis, the book goes on to pay particular attention to the contribution that surface science is making to our understanding of catalysis. It concludes with chapters devoted to carefully chosen examples of real catalytic systems, including catalytic action by enzymes and industrial processes based on solid catalysis. Looking to the future, the book introduces many novel types of catalysis.