In Western historical consciousness, National Socialist mass murder has become permanently identified with the Jewish Holocaust, Adolf Hitler's maniacal project to annihilate European Jewry. From its earliest days, the Nazi Party sought to exclude Jews from German public life, and when the Nazis came to power in January 1933, their anti-Jewish animus became official policy. What followed was legal disemancipation of German Jews, physical attacks on their persons, ghettoization, deportation, and physical extermination in the East. The story of the Holocaust is well known and generally accepted. Yet two years before German Jewish policy swerved from persecution and harassment to genocide, the Nazis were already involved in state-organized killing of another disfavored minority. Unlike the destruction of European Jews, the murder of this group—the mentally disabled—occurred within the Reich's own borders. Launched with the signing of a “Hitler decree” in October 1939 (backdated to 1 September), the centrally organized program targeted so-called “incurable” patients, whose lives were to be ended by a doctor-administered “mercy death” (Gnadentod). The Nazis attached the term “euthanasia” to their program of destruction, bolstering their rationale for it with humanitarian arguments and cost-based justifications, the latter legitimizing euthanasia as a means to free up scarce resources for use by “valuable” Germans. Over time, the restrictive use of euthanasia just for incurable patients ended; thereafter, the Nazis extended the killing program to healthier patients, sick concentration camp inmates, Jewish patients, and a variety of “asocials” (juvenile delinquents, beggars, tramps, prostitutes). The technology of murder developed in the “euthanasia” program—carbon monoxide asphyxiation in gas chambers camouflaged as shower rooms—would become the model for the first death camps in Poland. Many of the “euthanasia” personnel were likewise transferred to the Polish extermination centers, where they applied the techniques of mass death—refined in murdering the disabled—to the murder of the European Jews.