For this sixth edition of this well-established book the carefully selected material has been the subject of a reorganisation which is on a more ambitious scale than that preferred for previous new editions over the last decade. The book's insistence on the study of the law of the European Union in its wider social and economic context has been faithfully maintained and much will remain familiar to the regular reader. But for this sixth edition the customary rigorous process of up-dating has been combined with some re-structuring of the book's chapters as part of a process designed to ensure the book reflects the depth and breadth of policy-making regulatory activity now undertaken under the deceptively simple label of EU law. The book therefore introduces the student to the shifting sands of the three-pillar structure of the European Union as well as to the impacts of the Treaty of Nice and the adventurous expansion of the EU into Central and Eastern Europe. Furthermore, the book's well-established strengths in the field of core constitutional and substantive EU law, including the law of the internal market, are fully represented once again in this new edition and are supplemented by material dealing with flexibility, subsidiarity and emerging novel forms of governance for a geographically and functionally expanded Union. The book concludes as it begins - by interrogating the fascinating debate about the construction of a type of Constitution for Europe.