Due to the hereditary fragmentation of its external representation, the European Union's structures and procedures for international action differ significantly across policy fields. Reforms aimed at improving coherence have primarily concerned traditional areas of foreign policy and security policy. This edited volume examines the EU's external action in a broader spectrum of policy fields, such as energy and climate, trade, economics and finance, as well as labor and social policy. The book contributes to the present discussion on the development of the external action of the EU after the institutional reforms introduced by the Lisbon Treaty. In analyzing structures and procedures of external representation in selected policy fields with diverging degrees of integration, the volume explores the advantages and drawbacks of their specific models of external action. The contributing academics and practitioners reveal a clear challenge for the EU to improve the coherence, efficiency, and legitimacy of a joint representation of interests, in order to become a more relevant actor in the rapidly changing international environment.