Paul Craig is Professor of English Law at St John's College. He is a series editor of Oxford Studies of European Law and has published widely on EU law. Herwig Hofmann is Professor of European and Transnational Public Law at the University of Luxembourg. He is a co-author of Administrative Law and Policy of the European Union (OUP, 2011). Jens-Peter Schneider is the Legal Advisor of the Rector Chair for Public Law at the University of Freiburg and a Visiting Professor at Columbia Law School. Jacques Ziller is Professor of European Union Law at the University of Pavia. He is co-author of The European Constitution: Cases and Materials in EU and Member States' Law (Edward Elgar, 2007).