Abstract
The environmental movement in the United States traces its organizational roots to the turn of the twentieth century, and some of the membership organizations created during that period—especially the Sierra Club (1892) and the National Audubon Society (1905)—are still major players today. Other organizations, such as the Wilderness Society (1935) and National Wildlife Federation (1936), were established in subsequent decades, but the real explosion of growth that gave birth to the contemporary environmental movement occurred in tandem with other social movements of the 1960s. In the latter half of the 1960s and the first half of 1970s, important