The essays and commentaries in this collection were presented at a Con ference on Problems of International Law in the Western Hemisphere, the Second Conference on Problems of Regional International Law under the joint sponsorship of the American Society of International Law and the Graduate Faculty of the New School for Social Research, April 2 & 3, 1971. Contributors have been given the opportunity to revise their papers since their original presentation. The editors acknowledge with gratitude the important contributions made by the Chairmen of the respective panels, namely, Professor Louis Henkin of Columbia Law School (Water Resources Panel), Professor Richard B. Lillich of the University of Virginia Law School (panel on Intervention) and Dr. Egon Schwelb of the United Nations (Human Rights Panel). The assistance of the Graduate Faculty of the New School for Social Research in the organization of the conference and that of the New York University Center for International Studies in the editing of these papers have been indispensable. We wish to make particular mention of the unstinting secretarial support of Ms. Donna Welensky and Ms. Judith Chazen. Certain problems would have been insuperable without the critical (in all senses) aid provided by Lyn Rodley. . The descriptions of contributors are those that obtained at the time of the conference. Since then, Professors Rovine and Rodley have moved to new pastures, the former to the Department of State's Office of the Legal Adviser, the latter to Amnesty International, while Dr.