The law of the European Union is famous for its complexity, heteroge­ neity and diversity.It is also famous for its contested status. If a book is nevertheless called 'The Unity of the European Constitution', it should therefore raise some expectations. It might raise even more expecta­ tions, once the reader realizes that it presents a consequent binational discussion of such contentious issues. nd The book contains the contributions to the 2 German-Polish Seminar on the Constitutional Law of the European Union. The seminar was held from 11-15 May 2005 in Wrodaw under the auspices of the Max Planck Institute for Public International Law and Comparative Law in Heidelberg, supported by its director, Professor von Bogdandy, the Faculty of Law, Administration and Economics of the University of Wrodaw, especially Professor Wojtowicz and his Chair for Interna­ tional and European Law, and the Willy-Brandt-Center for German and European Studies in Wrodaw.1t was organized on the German side by Dr. Karen Kaiser, Dr. Jiirgen Bast, Stephan Bitter and Dr. Philipp Dann, and on the Polish side by Dr. Robert Grzeszczak, Dr. Michal Rynkowski and others.