Published by Prentice Hall in 2005, the book obviously doesn't contain any open source license versions that were created after that time. So the latest revision of the General Public License (GPL), created in the wake of a Microsoft-Novell deal with disturbing implications for open source software, is not in here. But that hardly matters; this book is about the principles on which open source licenses are based. While those can certainly change, they haven't changed enough since the time this book was published to make it any less relevant today.

There is no question that Lawrence Rosen is the right person to have written this book. He is a founding partner of a California-based technology law firm specializing in intellectual property protection, licensing and business transactions for technology companies. The Open Source Initiative (OSI) has benefited from his expertise, as have the Apache Software Foundation and other open source projects. But before he turned to law, Rosen belonged to the world of computers; he managed computing activities and taught computer programming and database design at Stanford University; he also worked in industry where he coordinated the design, development, manufacturing and marketing of data communications products. If anyone can understand the intersection of the legal and technological worlds brought about by open source licensing, surely it is Rosen.

In his acknowledgments he mentions that he had "the great good fortune to learn about open source from the leaders who created it" and lists some of most prominent names in the open source software movement, including Bruce Perens, Eric Raymond, and Richard Stallman. That gives Rosen added authority when he takes apart various open source licenses later in the book and talks about their creators' intentions.

The book covers the topic in 13 main chapters, plus extensive appendices that include verbatim copies of every license covered in the book. There is also a fairly complete index.