Introduction 73

By providing an environment for encoding knowledge, editing the evolving knowledge base, and testing programs, these systems provide techniques and tools that promise to be very versatile in helping to design new medical expert systems. While the earlier chapters in this volume provide motivation for applying artificial intelligence techniques to medicine, comparing the methods to those of traditional algorithmic programming and statistics, in this paper Kulikowski presents the knowledge-based perspective as a whole. This serves as a prelude to detailed discussions of particular consultation systems (Chapters 5, 6, 7, and 8) and to Szolovits and Pauker's analysis of medical reasoning in the context of these programs (Chapter 9).