Is the concept of Direct Effect of EC Law out of date? Or does it need to be revamped as a keystone doctrine of EC Law? This was the central theme of the international conference organized in June 2001 at the University of Amsterdam by the Hogendorp Centre, the Amsterdam Law School, the Amsterdam Centre of International Law, the Europa Instituut and the Amsterdam Jean Monnet Platform. The conference brought together speakers from The United Kingdom, Belgium, France and The Netherlands, to address the topic not only from the perspective of EC law, but also from those of domestic constitutional law and public international law. Their contributions reflect the various dimensions of direct effect as a central doctrine of EC Law.