‘Don’t take it seriously’ is a quote from the ‘Erasmus Mundus song’, written by Roger Van den Bergh at the occasion of the Erasmus Mundus recognition of the European Master in Law and Economics. Or, as Roger likes to call it, the European Master in Law and Comics. This quote is so characteristic of Roger, that it now serves as the title of this Liber Amicorum, with which we express our friendship with and gratitude towards Roger, for his outstanding contribution to Law and Economics.Through his combined part-time chairs in Law and Economics in several countries, his subsequent appointment in Rotterdam to the first full-time chair in Law and Economics in Europe, as well as his long presidency of the European Association of Law and Economics, Roger has advanced and shaped the development of the Economic Analysis of Law.This Liber Amicorum brings together the contributions of 43 authors, in honour of Roger Van den Bergh. The contributions encompass many different topics, which reflects Roger’s broad research interests. They are grouped together in four parts: Competition Law and Economics, Public Law and Economics, Private Law and Economics and Developments in Law and Economics. Many of the contributions contain links to Roger’s work, as well as the authors’ personal reflections on the importance of Roger for their work. This personal touch makes this Liber Amicorum, truly, a Friends Book for Roger.