Volume 4 (2013) of the European Yearbook of International Economic Law (EYIEL) offers a special focus on recent developments in International Competition Policy and Law. International competition law is emerging as a distinct subfield of international economic law in recent years even though international agreements on competition cooperation date back into the 1970s. Competition law became a prominent subject of political and academic debates in the late 1990s when competition and trade were discussed as one of the Singapore subjects in the WTO. Today, international competition law is a complex multi-layered system of rules and principles encompassing not only the external application of domestic competition law and traditional bilateral cooperation agreements but also competition provision in regional trade agreements and non-binding guidelines and standards. Furthermore, the relevance of competition law for developing countries or the relationship between competition law and public services raise controversial debates. The contributions to this volume reflect the growing diversity of the issues and elements of international competition law. The effectiveness of competition law is intrinsically linked to the institutional design of competition authorities. In his distinguished essay, William E. Kovacic revisits this classical theme of competition law and develops characteristics of good agency practice reflecting in particular his own experience and expertise as a former Chairman of the US Federal Trade Commission. The next set of essays addresses the relationship between trade law and competition law. Alden Abbott and Shanker Singham argue that both fields serve similar welfare-enhancing goals despite distinct legal traditions and support their case with an analysis of anticompetitive market distortions in the WTO and the International Competition Network (ICN). The essays by Hanspeter Tschaeni and Vale´rie Engammare and by Peter Hilpold supplement the trade and competition debate by studying the role of competition law in regional trade agreements (RTAs). Tschaeni and Engammare recall the growing importance of RTAs for competition law and share insights from the negotiators perspective. Hilpold takes the debate one step further and asks whether RTAs can serve as a stepping stone towards a plurilateral (or even multilateral?) agreement on competition law.