How can we comprehend the sociopolitical processes that give rise to extreme violence, ethnic cleansing, and genocide? A major breakthrough in comparative analysis, Purify and Destroy demonstrates that it is indeed possible to compare the Holocaust, the Rwandan genocide, and ethnic cleansing in Bosnia-Herzegovina while respecting the specificities of each appalling phenomenon. Jacques Semelin achieves this, in part, by leading his readers through the three examples simultaneously. His method is multidisciplinary, relying not only on contemporary history but also on social psychology and political science. Based on the seminal distinction between massacre and genocide, Semelin identifies the main steps of a general process of destruction, both rational and irrational, born of what he terms "delusional rationality." He describes a dynamic structural model with, at its core, the matrix of a social imaginaire that, in responding to fears, resentments, and utopias, carves and recarves the social body by eliminating "the enemy." Finally, he develops an intellectual framework to analyze the entire spectrum of mass violence, including terrorism, in the twentieth century and before. Strongly critical of today's political instrumentalization of the notion of "genocide," Semelin argues that genocide research should stand back from legal and normative definitions and come of age as its own discipline in the social sciences.