Setting aside the destruction of the biosphere, nothing in the ugly spectrum of human wrong- and evil-doing is worse than genocide. It is the most Satanic of evil acts, an “odious scourge” upon humanity, as the U.N. Convention on Genocide puts it. It appears early in the historical record, when the despots of antiquity built monuments and sang songs celebrating the slaughter of foreign populations. But it is in the modern period that genocide appears with a frequency, intensity, and magnitude far surpassing early tyrants and marauders. Throughout the twentieth century and continuing to the present day, genocide has been uninterrupted. Armenians, Jews, Gypsies, Homosexuals, Communists, Kulaks, Tutsis, Capitalists, Kurds, Sudanese, Syrians, a...