Book excerpt: The controversial question of whether or not at present the precautionary principle is to be considered a norm of customary international law is the key theme of this work, which treats the issue as part of a broader discussion of the principle's legal status on the international plane. This discussion, In turn, Is put in perspective by an account of the short but remarkable history of the principle in international environmental law and policy. The greater part of this study consists of the mapping and analysis of state practice in respect of the precautionary principle. Pertinent treaties, declarations, decisions of international organizations and domestic instruments pass in review. The book then applies the generally accepted principles governing the formation of customary international law to this body of state practice. This manuscript was awarded the François Prize 2001 by the Netherlands Society of International Law / Netherlands Branch of the ILA. `[The precautionary principle] has been cited in an increasing number of legal proceedings, including those in the International Court of Justice, The International Tribunal For The Law of the Sea And The WTO Appellate Body, As well as in the courts of a large number of states, including the supreme courts of India and Canada.' (from the Preface by the Series Editors)