The purpose of this book is to put together what I see as the main contributions of applied game theory, over the last two decades, to a better understanding of how collusion works and what antitrust authorities should do – and can do – about it. Insights into the economics of collusion detection and prevention should, by the same token, give a better idea of what sort of competition these authorities should aim for.

The results obtained have some general validity, in the sense that they do not depend on the particular legal framework in which competition policy is pursued. However, the choice of topics and of applications to particular antitrust cases refers to decisions taken by the Commission of the European Communities (EC) and judgements made by the European Court of Justice. It is appropriate therefore to start this preliminary chapter with a brief non-technical description of competition law in the EC, the more so as the different parts of the book correspond to different pieces of legislation.

A few basic game-theoretic concepts are then introduced, so as to allow the non-specialised reader to follow a critical discussion of the main features of the policy that appears to have been adopted by the Commission in order to stimulate what is sometimes called ‘normal’ or ‘active’ competition. This discussion sets the scene for a more thorough analysis to be developed in the ensuing chapters. The last section gives an outline of the book.