Martti Koskenniemi is Professor of International Law at the University of Helsinki and Director of the Erik Castren Institute of International Law and Human Rights. He worked as diplomat with the Finnish Ministry for Foreign Affairs from 1978 to 1994, representing Finland in a number of international institutions and conferences. As member of the UN International Law Commission (2002 6) he chaired the Study group on the 'Fragmentation of International Law'. He has written widely on international law topics and his present research interests cover the theory and history of the field.