Based on extensive archival research, this book offers the first historical examination of the arrest, trial, and punishment of the leaders of the SS-Einsatzgruppen - the mobile security and killing units employed by the Nazis in their racial war on the eastern front. Sent to the Soviet Union in the summer of 1941, four units of Einsatzgruppen along with reinforcements, murdered approximately one million Soviet civilians in open air shootings and in gas vans and, in 1947, twenty-four leaders of these units were indicted for crimes against humanity and war crimes for their part in the murders. In addition to a describing the legal proceedings, this book also examines recent historiographical trends and perpetrator paradigms and expounds on such contested issues as the timing and genesis of the Final Solution, the perpetrators' route to crime and their motivation for killing, as well as discussing the tensions between law and history.