Alan Boyle is Professor of Public International Law at University of Edinburgh. He was General Editor of the International and Comparative Law Quarterly from 1998 until 2006 and occasionally practises in the International Court of Justice and other international tribunals, mainly in environmental and law of the sea cases. Catherine Redgwell is Chichele Professor of Public International Law at All Souls College, University of Oxford. She is Joint Editor of the British Year Book of International Law and Co-Editor of Oxford Monographs in International Law. The late Patricia Birnie was a Visiting Fellow at the London School of Economics. She was one of the world's foremost international environmental lawyers; her advice was sought by prominent NGOs such as the International Union for the Conservation of Nature and by various governments in her lifetime.