The present volume originates from a two-day conference, EU External Relations Law and Policy in the Post-Lisbon Era, hosted by the Sheffield Centre for International and European Law (SCIEL) at the School of Law, University of Sheffield on 13 and 14 January 2011. The conference was generously funded by the Modern Law Review and the University Association for Contemporary European Studies (UACES). Participants at the conference were invited to consider the scope, nature and practice of EU External Relations Law and Policy in the Post-Lisbon Era. At the time of the conference, the Treaty had entered into force some 13 months earlier, so authors were able to reflect on some of the immediate consequences—both theoretically and practically—brought about by the Treaty as well as some of the incremental changes occurring during the period of Treaty reform. The response and the breadth of papers discussed was testament to the healthiness of EU external relations as a research area. The approach taken was deliberately interdisciplinary in order to promote a wide understanding of the contemporary nature of this dynamic field of study.