Be it the illegal downloading of music on the Internet or the sale of fake designer products on street comers, intellectual property is under attack these days. For many, intellectual property is a barrier to commerce and the sharing of ideas, a zero-sum game between the creator and the rest of the world. Cass and Hylton, authors of this cogent and readable book, disagree, arguing that the protection of intellectual property enhances social welfare and creativity. The book offers a good overview that defines what intellectual property is, explains why ideas are protected, and then provides successive chapter discussions of its four major components: patent, trade secrets, copyright, and trademark law. Each chapter explains the law and the economic justification of each type of law. The authors also discuss the challenges of protecting intellectual property in a global economy and under terms of rapidly changing technology. This is an excellent book for those wishing to understand how and why many common practices such as file swapping on the Internet threaten creativity.