Are international boundaries necessarily an obstacle to effective environmental management? the ever-increasing competition between states for access to natural resources may represent a threat not only to ecological stability but to regional and even global security. Or perhaps transboundary environmental issues can actually have a positive impact on international relations, encouraging states to cooperate and building confidence between previously hostile neighbours. Drawing on a wide range of case studies, The papers in this volume explore these important issues from a multi-disciplinary perspective. Contributions from practitioners and technical experts complement detailed studies by geographers, lawyers, and political scientists. This mix yields a unique survey of (1) problems when environmental systems cross international borders and (2) transboundary cooperative projects designed to reduce the threat of ecological catastrophe and political conflict between competing neighbours around the world. The conclusion: Despite the daunting challenges there exist grounds for optimism. This collection is based on the proceedings of an international conference held in Singapore in June 1995, co-hosted by the Centre for Advanced Studies And The Department of Geography, National University of Singapore And The International Boundaries Research Unit, University of Durham, United Kingdom and is essential reading for anyone interested in understanding the complex relationship between boundaries, environment and international security.