Environmentalism -- defined here as activism aimed at protecting the environment or improving its condition -- is undergoing significant change in the United States. Under attack from the current administration and direct questioning from its own ranks, environmentalism in the US is at a crossroads. This special issue will explore the changing patterns of and challenges to environmentalism in the contemporary US. More specifically, it will examine the following dynamics: * the re-conceptualisation of core ideas and strategies defining US environmentalism; * questions of identity and relations with other advocacy groups (including labour, global justice and women's groups); * institutional change (especially the shift away from regulatory policies and approaches); * the expanding arenas of activism, to both above and below the state; * environmentalists' response to Bush administration policies and priorities. This book was previously published as a special issue of Environmental Politics.