The Sierra Club is one of the largest environmental organizations in the United States. It was founded in 1892 by nature writer John Muir. The purpose of the Sierra Club is to protect and preserve the natural environment. During the past century, the club has become well known for its aggressive efforts to block projects it deemed harmful to the earth's ecosystem.

In the 1960s, the Sierra Club found itself embroiled in one of its greatest battles. This time though, unlike other confrontations, this struggle centered on members of the organization--specifically, its executive director David Brower.

David Brower, a longtime champion of environmental issues and a man very similar in qualities to John Muir, developed the Sierra Club from a fledgling organization of just over seven thousand members into a membership of over seventy thousand by the late 1960s. As executive director, Brower advanced the club's reach and objectives away from the image of a hiking organization into one that more actively pursued environmental issues. Brower's opponents argued that his actions centered more on him--some members even alleged that various illegal activities were taking place. The divisiveness of these numerous issues eventually led to the removal of Brower from the club in 1969. The Flannery collection contains documents and articles dealing directly with the controversy between David Brower and the Sierra Club.