Final Solutions focuses on three types of mass killing: communist mass killings like the ones carried out in the Soviet Union, China, and Cambodia, ethnic genocides as in Armenia, Nazi Germany, and Rwanda, and "counter-guerrilla" campaigns including the brutal civil war in Guatemala and the Soviet occupation of Afghanistan. Valentino closes the book by arguing that attempts to prevent mass killing should focus on disarming and removing from power the leaders and small groups responsible for instigating and organizing the killing.