To the American public it's a 2,000-mile-long project to keep illegal immigrants, narcotics, and terrorists on the other side of the U.S.–Mexico border. In the deserts of Arizona, it's a “virtual fence” of high-tech electronic sensors, cameras, and radar. In some border stretches it's a huge concrete-and-steel wall; in others it's a series of solitary posts designed to stop drug runners; in still others it's rusted barbed-wire cattle fences. For two-thirds of the international boundary it's nonexistent. Just what is this entity known as “the fence”? And more important, is it working? Through first-person interviews with defense contractors, border residents, American military, Minutemen, county officials, Customs and Border Protection agents, environmental activists, and others whose voices have never been heard, Robert Lee Maril examines the project's human and financial costs. Along with Maril's site visits, his rigorous analysis of government documents from 1999 to the present u