This book takes as its starting point the interaction and gaps between the free movement and competition rules of the EC Treaty. Competition and free movement are well known as fundamental elements of the Community legal order and are normally treated separately by different specialists. Hence their interaction has tended to receive less doctrinal analysis. This work bridges the gap and examines the interaction of these disparate rules using a framework which is defined by the author as the economic constitutional law of the European Community. The book then examines in depth specific issues such as, for example, the economic orientation of the constitution of the Community, the structure and principles of interpretation relating to it or the gaps presented by this structure and the ways in which they have been filled by the European Court of Justice. Particular attention is given, in separate chapters, to two important topics: the possible extension of the application of the free movement rules to protectionist private conduct and that of the competition rules or principles extracted from them to State action.