This book summarizes the current knowledge regarding expert systems. It is informative and well organized. The book is good for technical professionals who want to know the state of the art in the field of expert systems. It draws from a wide variety of sources and lists a wide range of centers and companies that research and develop expert systems. The book covers the breadth of the field but does not go into depth. For this reason it is not an appropriate book for a computer science curriculum. Another drawback of the book is that the information presented is biased towards one specific manufacturer. It is, though, an excellent reference book on expert systems. The discussion on software and hardware used in expert system development and execution is comprehensive and quite useful. Overall the book is a welcome addition to the numerous books on expert systems published recently.