This volume examines the roles of different actors in the formulation of international and national environmental policy. It starts from the premise that while cooperation among nation states has proven to be necessary to address many transboundary environmental issues, virtually all policies must be implemented at the national or local level. The growing interaction between national and international actors and levels of governance is an increasingly important aspect of international environmental policy. The authors examine the roles of state and non-state actors in safeguarding the environment and advancing sustainable development into the twenty-first century. Each of five sections focuses on a different actor: states, civil society, market forces, regional arrangements and international organizations. By examining the functions and capabilities of each of these actors, the authors analyse their effectiveness and their relationship with other actors both within and outside of the UN system, providing a useful framework for understanding the multi-actor, multi-issue nature of international environmental policy.