The book—really an extended essay—argues that Stalin’s mass killings in the 1930s should be classified as “genocide.”The book suggests that the definition of genocide, as taken from the work of Raphael Lemkin and the 1948 United Nations Convention on the Prevention and Punishment of the Crime of Genocide, should be broadened to include social and political groups.The obligation of protecting ethnic and national groups, as well as religious and racial ones, from mass murder should not obviate the need to protect political and social groups from the same horrendous crime.In particular Stalin’s crimes should not be excluded from our consideration of genocide because the Soviet Union successfully lobbied against the inclusion of social and political groups in the Genocide Convention in the first place.The book goes on to examine Soviet mass killing in the 1930s, demonstrating that Stalin was fully in charge of and aware of the consequences of these genocidal events. They were examples of intentional mass killing carried out by the police apparatus of the Soviet state.Among the episodes I consider in the book are: dekulakization, the Ukrainian killer famine of 1932-33, the assault on targeted Soviet nationalities, the elimination of “asocials” or “socially harmful people” as a consequence of Order 00447, and the Great Purges.The “rationale” for Soviet mass killing is also examined in the book, including the “war fear” argument.