Glen Canyon Dam became the subject of influential literature, including Edward Abbey's novel "The Monkey Wrench Gang" (1975), which tells the story of a fictional group of environmentalists fighting against industrial developers in the American Southwest, their ultimate target being Glen Canyon Dam. The novel gained a cult following after its publication and established Glen Canyon Dam as a poster child of environmental destruction caused by dams. Abbey's book is discussed in "Ecospeak: Rhetoric and Environmental Politics in America" (1992) by Jimmie Killingsworth and Jacqueline Palmer, who write that Glen Canyon Dam became "the big symbol of all that blocked freedom in the interests of civilized progress." On March 21, 1981, the radical environmental group Earth First! staged an anti-dam protest by unfurling a tapered black sheet of plastic down the face of the dam, making it appear as if a gigantic crack had appeared in the structure – a direct re-enactment of a scene from Abbey's book. Authorities were unable to find the individuals responsible.