Spencer provides a history of the FMLN guerrilla special forces--known collectively by the acronym FES--in El Salvador. Trained in Cuba and Vietnam, they utilized techniques taken from the Viet Cong and the North Vietnamese army. From 1981 to 1992, the FES terrorized the armed forces of El Salvador. It was only toward the end of the war that the FES became less effective, largely due to attrition and casualties. After reviewing their training, Spencer looks at the major operations of the special forces groups of three of the guerrilla factions--the FPL, ERP, and FAL--and provides an in-depth discussion of their major operation tactics and methods. He concludes with a look at the special forces groups in Argentina, Colombia, Cuba, Guatemala, Nicaragua, and Puerto Rico. This thorough examination of an often misunderstood approach to guerrilla warfare will be of great interest to researchers involved with contemporary low-intensity warfare and Latin American affairs.