As the 110,000 residents of McAllen, Texas, sleep soundly, a small number of U.S. Border Patrol agents wait in dark shadows on the northern bank of the Rio Grande. Those thinly spread watchers are the first line of defense against a chaotic tide of undocumented workers struggling to cross the river to El Norte and small, fiercely determined groups of drug smugglers with huge sums of money at stake. Patrolling Chaos is based on extensive ethnographic field work focusing on one station of three hundred agents over a two-year period. It follows twelve typical agents, men and women, as they go about their regular ten-hour patrols along the border. It describes the daily challenges and risks they face and the perspectives and insights they hold as a result of their extensive, first-hand experience with the hard realities of immigration policy, the war on drugs, and the threat of terrorist infiltration. Robert Lee Maril writes about the surveillance and apprehension of thousands of undocumented workers, drug interdictions involving huge quantities of marijuana and cocaine, the deaths of illegal immigrants by drowning and as a result of high-speed chases, corruption among law enforcers, and other events that shape the work lives of agents. The book also describes the impact of the 9/11 attacks on border security and on the personal lives of the agents and their families. This account of the world of U.S. Border Patrol agents will contribute to a more comprehensive understanding of our border with Mexico, the people and the resources of the borderlands, the constant flow of illegal immigrants and drugs, and new challenges confronting the enforcement of laws and policy in light of international terrorism.