Valentino develops his mass killing concept through eight-case studies, three of which fit the legal definition of genocide (the Armenian genocide, the Holocaust, and the Rwandan genocide), while the other five are about politicide cases of the Soviet Union under Joseph Stalin, Communist China under Mao Zedong, Democratic Kampuchea under the Khmer Rouge, the anti-communist regime in Guatemala (the Guatemalan genocide), and Afghanistan during the Soviet–Afghan War. Although he does not consider ideology or regime type as an important factor that explains these killings, Valentino outlines Communist mass killing as a subtype of dispossessive mass killing, which is considered as a complication of original theory his book is based on. In regard to Communist mass killings, Valentino does not connect them and only discusses the Stalin era, the Mao era, and the Khmer Rouge rule of Cambodia, and excludes counter-insurgency mass killings, which he groups in his book with similar killings by capitalist regimes; they were not ideologically driven but resulted from the same motivations as non-Communist states.