ABSTRACT
Far too much has been written about expert systems already, and in this brief chapter I have no intention of rehashing the time-worn examples of MYCIN, TEIRESIAS, R1, etc. going through their repertoire of tricks. The purpose of this chapter is to satisfy the obligation to provide some survey of this AI subfield in a book that is about the engineering of AI-software systems, for expert systems do have a strong claim to be the major area of practical application of AI tools and techniques. But this claim is not accepted by all who are in a position to evaluate it critically. This subfield, like most AI-related phenomena, is not devoid of contention and disputation, far from it.
