Mixed agreements are one of the most significant and complex areas of EU external relations law. They are concluded by the Member States and the EU (or the European Community in the pre-Lisbon days) with third countries and international organisations. Their negotiation, conclusion and implementation raise important legal and practical questions (about competence, authority, jurisdiction, responsibility) and often puzzle not only experts in countries and organisations with which the EU works but also European experts and students. This book, based on papers presented at a conference organised by the Universities of Leiden and Bristol in May 2008, provides a comprehensive and up-to-date analysis of the legal and practical problems raised by mixed agreements. It brings together the leading international scholars in the area of EU external relations, including two Judges at the European Court of Justice and a Judge at the EFTA Court, along with legal advisors from EU institutions, Member States, and third countries.