The purpose of "Artificial Intelligence Techniques: A Comprehensive Cata­ logue" is to promote interaction between members of the AI community. It does this by announcing the existence of AI techniques, and acting as a pointer into the literature. Thus the AI community has access to a common, extensional definition of the field, which promotes a common terminology, discourages the reinvention of wheels, and acts as a clearing house for ideas and algorithms. I am grateful to the impressive group of AI experts who have contributed the many descriptions of AI techniques which go to make up this Catalogue. They have managed to distill a very wide knowledge of AI into a very compact form. The Catalogue is a reference work providing a quick guide to the AI tech­ niques available for different tasks. Intentionally, it only provides a brief de­ scription of each technique, with no extended discussion of its historical origin or how it has been used in particular AI programs.