EU competition law plays a central role in the process of European integration both as a multifaceted tool for creating and policing the internal market as well as in organising national markets. Yet as a consequence of this role it is also subject to increasingly complex demands, a proliferation of (sectoral) regimes, and multiple objectives at both an EU and national level. This profligacy entails risks of fragmentation and divergence - which could jeopardise the proper functioning of the internal market. In this examination of EU competition law, Wolf Sauter discusses three main issues: (i) what degree of coherence exists in EU competition law; (ii) how this coherence can be explained, particularly in the broader context of integration by EU law; and (iii) how it contributes to the legitimacy and effectiveness of EU competition law. Specific focus is placed on antitrust, while mergers, state aid control, as well as the sectoral regimes for energy and electronic communications are also examined. In addition the book also charts the history and framework of these competition regimes that jointly constitute EU competition law, defining both its objectives and limitations.