The Prentice Hall Essence of Computing Series provides a concise, practical and uniform introduction to the core components of an undergraduate computing degree. Acknowledging the recent changes within Higher Education, this approach uses a variety of pedagogical tools - case studies, worked examples and self-test questions - to underpin the student's learning. This concise text combines an understanding of the theoretical principles and techniques with the development of practical skills needed to build expert systems. The most commonly used software tools for building expert systems-expert system shells-are used to give students practical experience.