Whether the stakeholders include public, nonprofit, or exclusively private participants, collaboration is increasingly favored over regulatory enforcement or litigation as a means to settle environmental conflicts. At the urging of citizens, nongovernmental organizations, industry, and individuals within their own institutions, government officials at all levels have been experimenting with collaboration in a wide variety of contexts. Yet questions remain about the best way to ensure that government involvement will be constructive -- that is will support collaboration, rather than introduce barriers. The goal of this thoughtful work is to analyze data from a variety of cases to explain how the different roles government plays in collaborative environmental management lead to different processes and outcomes. Looking at examples where government has acted to lead, encourage, or follow in the process of collaboration, they apply their new theoretical framework to cases involving the management of watersheds, rivers, and estuaries to farmland, animal habitats, and forests. Finding that there is no "best" role for government; the authors are nonetheless able make important observations about when and where collaborative environmental management is likely to be effective..