This book examines the military organization, strategy, and tactics of the Salvadoran FMLN guerrillas during their efforts to overthrow the government. It is largely based on the authors' personal collections of guerrilla documents captured in the war, interviews with former and captured guerrillas, and personal combat experience during one of the fiercest wars fought in the Western hemisphere in the 20th century. The book describes the guerrilla tactics from a technical point of view, and their evolution during the war in El Salvador.