As the residents of McAllen, Texas, sleep soundly, a small number of agents of the U.S. Border Patrol wait in dark shadows on the northern bank of the Rio Grande. Those few, thinly spread watchers are the first line of defense against a chaotic tide of undocumented workers and determined drug smugglers with only one goal in mind: to cross the river to el Norte. Patrolling Chaos is based on extensive ethnographic field work focusing on one station of three hundred Border Patrol agents over a two-year period. Following twelve typical agents, men and women, as they go about their regular ten-hour patrols along the border, the book describes the daily risks they face and the 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 spent two years observing the surveillance and apprehension of thousands of undocumented workers and drug interdictions involving huge quantities of marijuana and cocaine as well as the deaths of illegal immigrants, corruption among law enforcers, and other events that shaped 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 rarely documented view of the world or agents of the U.S. Border Patrol 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.