In the world of information, according to Stuckenschmidt and van Harmelen, some problems cease to be significant, and some remain. They identify producing online, digitized information, as well as storing such information and transporting it, as issues that are no longer a problem. However, they blame solutions to these problems for having created the most urgent remaining problems: information finding and information integration, together called information sharing, which is the problem of finding pieces of information and meaningfully relating them with other pieces.

The main hypothesis of the book is that the problem of information sharing, as defined above, is only solvable by giving the computer better access to the semantics of the information. This may sound trivial, but the real challenge is in showing what additional information should be made available, and how it can be used to make the effective sharing of information possible. One obvious answer to the former question, which has been emerging from research results in recent years, is the use of metadata. More specifically, metadata should support the relating of important concepts that are discussed in the accessed document to other documents, and the relating of these concepts to general background knowledge. One concept (or technology) is ontology. The concept of ontology is of course much older (and, perhaps, also slightly different) than that used in connection with the semantic Web. Having arrived at the concept of the semantic Web, the authors then introduce all of the important concepts in information sharing on the semantic Web.

The book contains 12 chapters, and is organized into five parts. In the first part, “Information Sharing and Ontologies,” the concept of information sharing as understood by the authors is introduced, along with the crucial concept of the ontology, including languages for its representation for the semantic Web, in particular, resource description framework (RDF) schema and the Web ontology language (OWL). Part 2 is devoted to the process and methods of creating explicit representations of ontologies. Part 3 describes how the languages and representational structures can be used for information sharing, in particular for information retrieval, integration, and querying. Special attention is paid to sharing statistical information, and spatially related information.

In Part 4, the authors discuss the more fundamental issues of the distributed nature of the whole environment. The ontology might typically be distributed across the Web, so its modularization is a natural way of viewing such a phenomenon. The last part, Part 5, contains conclusions, and proofs of some of the more important theorems.

The book is not a textbook, and probably could not be used as one at this stage of the maturity of the field. The field is emerging, and the authors have succeeded in grasping some of the essential problems that are related to what they call information sharing. The field is not mature enough, however, to become a standard university discipline, and will not become one for some time. At the same time, the field is witnessing vivid research activity. The book presents a very good account of state-of-the-art research. The authors are themselves working in the field, and the book greatly benefits from this fact. Another very positive feature of the book is that the authors have succeeded in creating a comprehensive and coherent text that is more than a collection of papers. I recommend this work to all researchers and practitioners in information systems and related areas.