Book excerpt: The United States and the European Union operate the world’s two most powerful systems of competition law and policy, whose enforcement and judicial institutions employ similar concepts and legal language. Yet the two regimes sometimes reach very different results on significant antitrust issues. In The Atlantic Divide in Antitrust, Daniel Gifford and Robert Kudrle show that a combination of differences in social values, political institutions, and legal precedent inhibit close convergence. The book explores the main contested areas of contemporary antitrust: mergers, price discrimination, predatory pricing, exclusive supply, conditional rebating, intellectual property, and Schumpeterian competition. The authors explore how the prevailing antitrust analyses differ in the EU and the U.S., the policy ramifications of these differences, and how the analyses used by the enforcement authorities or the courts in each of these several areas relate to each other. Several themes run through the substantive areas treated in the book: pricing incentives and constraints, welfare effects, and whether competition tends to be viewed as an efficiency generating process or as rivalry. The notorious Microsoft case offers a useful lens to examine copyright, patents, and trade secrets, and the authors take the opportunity to contemplate competition policy in dynamic, innovative industries more broadly. For the EU, competition policy has also functioned as a mechanism to bond national markets together in the EU structure; the USA, federal from the beginning, did not require this instrumental aspect in its antitrust doctrines. The Atlantic Divide concludes with forecasts and suggestions about how greater compatibility, if not convergence, might ultimately be attained.