This book offers a timely and critical evaluation of the Chicago School approach to antitrust law. Recent judgements by the United States Supreme Court (in cases such as Kodak) and the debate surrounding the Microsoft monopoly have led to the view that antitrust has entered the post-Chicago era, in which previous immoderations are tempered, and more refined and accurate analyses take precedence. This claim is made at a time when European competition policy is gradually embracing an economics-based approach. The authors discuss the economic foundations of competition policy and the different ways in which both American and European competition law does – or does not – take account of economic insights. Although the book makes no claim to provide a definitive answer to the host of questions arising from the complexities of antitrust, it does offer an important contribution to a better understanding of the many ‘interfaces’ between economic thinking and sound legal policy.