The market for software tools that relieve expert system developers from programming basic mechanisms and enable rapid prototyping is currently evolving in an exceptionally dynamic manner. This applies to the number of providers as well as the number of products, and especially to the emergence of new versions with new features. The various tools offer individual users different advantages, but of course also disadvantages, for their specific purposes. This book is the result of a study on the availability of expert system tools in the Federal Republic of Germany. It systematically describes the application-relevant performance characteristics of expert system tools. It presents a classification of the products available on the market based on these performance characteristics. It offers users a selection process based on.