One of the key components of the modernization of competition rules has been a radical departure from the previous «form-based» enforcement to a so-called «effects-based» approach. Taking stock of ten years of experience under this new policy, the present book analyses the changes brought about, as well as the practical problems encountered in its day-to-day application, be it by competition law enforcers, judges or practitioners. This book compiles the reports prepared for the 2011 Annual Conference of the Global Competition Law Centre ("GCLC"). Each and every chapter of this volume formulates concrete proposals as to how the system can be clarified or even improved. The focus is not only on the enforcement of Articles 101 and 102 TFEU, but also in the file of merger control. Attempts are made to define more precisely the boundaries between anticompetitive object and effect, and to develop adequate safe harbours and presumptions. This book also casts a closer look at the analytical framework, possible theories of harm, evidence and defences. Overall the objective is to reconcile as best as possible law and economics, and to see how the goal to achieve the "right decision" in terms of economic outcome can be combined with the legitimate need for legal certainty.