This text reviews a variety of approaches to the study of the European Union's foreign policy. Much analysis of EU foreign policy contains implicit theoretical assumptions about the nature of the EU and its member states, their inter-relationships, the international system in which they operate and the nature and direction of European integration. In many instances such assumptions, given that they are not discussed openly, curtail rather than facilitate debate. The purpose of this book is to open up this field of enquiry so that students, observers and analysts of EU foreign policy can review a broad range of tools and theoretical templates from which the development and the trajectory of the EU's foreign policy can be studied.