Description logic (DL) is the name of a family of formal logics that are related to knowledge representation (KR). These have particular applications in connection with the semantic Web and other Web-based systems, as well as some applications in connection with databases.

This is the second edition of a work that initially appeared in 2003. It consists of 16 chapters and an appendix. The first chapter is a general introduction to the field, and the remaining chapters make up the book’s three main parts.

Part 1, “Theory,” consists of five chapters. The following indicates the flow of discussion in this part:

Because description logics are a KR formalism, and since in KR one usually assumes that a KR system should always answer the queries of a user in reasonable time, the reasoning procedures DL researchers are interested in are decision procedures. ... These procedures should always terminate, both for positive and for negative answers. Since the guarantee of an answer in finite time need not imply that the answer is given in reasonable time, investigating the computational complexity of a given DL with decidable inference problems is an important issue.

Part 2, “Implementation,” consists of chapters 7 through 9. The discussion in this part starts with early (1980s) KR systems, such as KRYPTON and KL-ONE, and continues on to their more contemporary DL successors.

Part 3, “Applications,” consists of seven chapters that discuss applications of DL (and its precursors) to ontology modeling, software engineering, the configuration of systems, medical informatics, the semantic Web, neurolinguistic programming, and databases. This is also the part of the book that many will find most interesting, since it conveys the sense of where the rubber meets the road. Chapter 11, “Software Engineering,” is especially interesting, but perhaps out of date since it doesn’t cite any work after 1995 (which may indicate that this line of work has not recently been popular in mainstream software engineering). A similar issue is also noticeable with respect to the other chapters in this section (except for chapter 14, “OWL”). One gets the sense that the DL approach has not found much application within the past decade, except in the semantic Web context.

On the whole, this book is a valuable resource for any scientist or institution working in areas related to applications implementation. As an anthology of essays written by top scholars in the field, it is generally very well put together. There are just a few minor issues (such as the persistent use of the en dash in place of the em dash and the occasional grammatical error) that some careful editing could address.