Abstract:This chapter reflects on multilateral environmental treaty making. From its inception, international environmental law has consisted primarily of treaties and other forms of negotiated instruments, which offer several advantages over more informal mechanisms of international cooperation. Traditionally, treaties were comparatively static arrangements, memorializing the rights and duties of the parties as agreed at a particular point in time. Today, environmental agreements are usually dynamic arrangements, establishing ongoing regulatory processes. The result is that, in most environmental regimes, the treaty text itself represents just the tip of the normative iceberg. Most norms are adopted through more flexible techniques, which allow international environmental law to respond quickly to the emergence of new problems and new knowledge. The chapter then introduces the basic types of international instruments, analysing why states negotiate and accept them. It describes the process by which agreements are created, from the inception of negotiations to the adoption and entry into force of the resulting instrument. The chapter also explores various design issues in developing international environmental agreements.