The most widely adopted text in the field for over two decades, this comprehensive, multidisciplinary casebook analyzes all aspects of international environmental law and policy, including the major environmental treaty regimes, customary law principles and the development and evolution of soft law norms. Written in a user-friendly fashion with problem exercises, it emphasizes the dynamic nature of the law-making process, including global environmental diplomacy and the critical role of non-state actors, including scientists, NGOs, and business. Getting to the heart of pressing environmental challenges, it explains not just the law but also the relevant politics, economics, and science. This sixth edition of the book reflects major new developments such as the development of rules to implement the Paris Agreement, the evolution of the Montreal Protocol ozone treaty into an explicit climate treaty, the emergence of successful human-rights litigation to address climate change, the withdrawal of Japan from the Whaling Convention, the U.S.-Mexico-Canada Trade Agreement, and the increasing concern over plastic pollution, to name just a few.