When Patrick McCartan asked me to prepare a second edition of The Economics of Imperfect Information for Cambridge University Press, I proposed rather to do a book that would give a coherent presentation of the main game-theoretic contributions to competition policy and include large chunks of the old chapters on oligopoly and collusion and on predatory pricing. I had indeed been writing up lecture notes for a course on applied microeconomic theory that aimed at doing just that. Patrick agreed without hesitation and encouraged me with enthusiasm. Here is the result.

The first colleague to thank is my departmental chairman, Mark Salmon, who talked me into teaching a ‘taught’ course. Without his bit of armtwisting I would not have thought of writing another book. Several of my Ph.D. students at the European University Institute in Florence showed a keen interest in the course and started working on my favourite topic: the detection of collusion. Some agreed (or even suggested) to contribute to the manuscript. Barbara Böhnlein accepted to have her work on the informational requirements of collusion detection in the soda-ash market (the ICI–Solvay case) included as section 8.4; Hans-Theo Normann tackled the question of how to distinguish predatory pricing from Stackelberg warfare and normal competition between duopolists in section 13.2; Valeria Fichera wrote section 4.3 on cartels in public procurement contracts. I am sure the reader will pinpoint these sections as particularly interesting and novel contributions.