Many of the frontiers of environmental economics research are at the interface of large-scale and long-term environmental change with national and global economic systems. This is also where some of the most of challenging environmental policy issues occur. Volume 3 of the Handbook of Environmental Economics provides a synthesis of the latest theory on economywide and international environmental issues and a critical review of models for analyzing those issues. It begins with chapters on the fundamental relationships that connect environmental resources to economic growth and long-run social welfare. The following chapters consider how environmental policy differs in a general-equiIibrium setting from a partial-equilibrium setting and in a distorted economy from a perfect economy.