This book is aimed at the Prolog programmer interested in either building expert systems or experimenting with various expert system techniques. Dennis Merritt chooses a step-by-step approach to building systems, explaining the concepts and showing the Prolog code at each stage. The book builds on simple beginning systems and progresses up to relatively sophisticated expert system tools. It does not emphasize techniques of logic programming or the particularities of Prolog, but rather, emphasizes Prolog as an efficient software development tool, and teaches how to build expert systems and design the necessary tools. It is recommended (but not required) that the reader use a Prolog interpreter along with reading this book to experiment with the various Prolog examples given throughout the text.