Understanding Knowledge as a Commons: From Theory to Practice edited by Charlotte Hess and Elinor Ostrom. Cambridge, Mass.: MIT Press, 2006. 381 pp. ISBN-10: 0-262-08357-4; ISBN-13: 978-0-262- The availability of knowledge in digital form is changing the way some scholars view knowledge. Charlotte Hess and Elinor Ostrom, both of Indiana University, join forces to produce this collection of essays about the concept of knowledge as a commons. The scholars who contribute to this book examine knowledge as a shared resource, much like an environmental commons. The book originated in a working session on scholarly communication as a commons in 2004, but the authors note that the idea of an information commons began to emerge in the mid-1990s. Although the editors have attempted to broaden the scope of the book beyond the workshop’s focus on scholarly communication, nearly all of the chapters deal with this topic. This is understandable, as all of the authors have connections with colleges or universities. This volume focuses on knowledge commons issues in the United States. A few international organizations and universities are mentioned, but the international issues related to the idea of a knowledge commons are not addressed here; specific legal and political concepts, such as copyright, are discussed from a U.S. perspective. The book is divided into three sections: “Studying the Knowledge Commons,” “Protecting the Knowledge Commons,” and “Building the Knowledge Commons.” The first three chapters explain and justify the application of the commons metaphor to knowledge. They also discuss problems the knowledge commons might face, such as free-riding or disappearing assets. The early chapters are all interrelated, with references to other chapters in the book. They discuss ideas for encouraging scholars to contribute to archives or depositories of knowledge products, but fail to fully consider why there might be resistance to contributing scholarly articles. The second section focuses on protecting the knowledge commons, largely by resisting enclosure, questioning copyright, and preserving electronic journals. The chapters in the final section of book focus on building the knowledge commons. Some of these chapters are theoretical “thought experiments,” while the last chapter is a case study of a digital library for economics. Although the editors note the differences between the knowledge commons and the idea of open access several times in earlier chapters, the two concepts become blurry in some later chapters. The concept of public domain is also mixed in, especially in discussions of copyright and open access. The book’s essays flow logically from one to the next, with a couple of exceptions. James Boyle’s provocative chapter, “Mertonianism Unbound? Imagining Free, Decentralized Access to Most Cultural and Scientific Material,”