In this comparative survey of guerrilla movements in Latin America, Timothy Wickham-Crowley explores the origins and outcomes of rural insurgencies in nearly a dozen cases since 1956. Focusing on the personal backgrounds of the guerrillas themselves and on national social conditions, the author explains why guerrillas emerged strongly in certain countries but not others. He considers, for example, under what circumstances guerrillas acquire military strength and why they do—or do not—secure substantial support from the peasantry in rural areas.