The word “Holocaust,” from the Greek words “holos” (whole) and “kaustos” (burned), was historically used to describe a sacrificial offering burned on an altar. Since 1945, the word has taken on a new and horrible meaning: the mass murder of some 6 million European Jews (as well as millions of others, including Gypsies and homosexuals) by the German Nazi regime during the Second World War. To the anti-Semitic Nazi leader Adolf Hitler, Jews were an inferior race, an alien threat to German racial purity and community. After years of Nazi rule in Germany, during which Jews were consistently persecuted, Hitler’s “final solution”–now known as the Holocaust–came to fruition under the cover of world war, with mass killing centers constructed in the concentration camps of occupied Poland.
While the Nazis murdered other national and ethnic groups, such as a number of Soviet prisoners of war, Polish intellectuals, and gypsies, only the Jews were marked for systematic and total annihilation. Jews were singled out for "Special Treatment" (Sonderbehandlung), which meant that Jewish men, women and children were to be methodically killed with poisonous gas. In the exacting records kept at the Auschwitz death camp, the cause of death of Jews who had been gassed was indicated by "SB," the first letters of the two words that form the German term for "Special Treatment."
Before the war, Mengele had received doctorates in anthropology and medicine, and began a career as a researcher. He joined the Nazi Party in 1937 and the SS in 1938. He was assigned as a battalion medical officer at the start of World War II, then transferred to the Nazi concentration camps service in early 1943 and assigned to Auschwitz, where he saw the opportunity to conduct genetic research on human subjects. His subsequent experiments focused primarily on twins, with little regard for the health or safety of the victims.