Encouraged by von Verschuer, Mengele applied for transfer to the concentration camp service to take advantage of the opportunity to conduct genetic research on human subjects. His application was accepted and he was posted to Auschwitz in the spring of 1943. Mengele first gained notoriety for supervising the selection of arriving prisoners to the camp, determining who would be sent to the gas chambers and who would become a forced laborer. This earned him the reputation as the “Angel of Death.” Whereas most of the other doctors viewed the selection process as one of the most horrible duties and had to get drunk in order to endure it, Mengele had no problem with the task. He often arrived smiling and whistling a tune, and even showed up for selections he wasn’t assigned to.
However, an examination of other variables suggests that rescuers shared a cluster of common personal characteristics. One of these can be called individuality or separateness. Polish rescuers often did not quite fit into their social environments. To illustrate, the peasant Jan Rybak, who helped save both Jews and Russian prisoners of war during the German occupation, had little formal education but was nonetheless a compulsive reader. His knowledge and love for learning gained him the nickname philosopher. Moreover, he avoided alcohol and did not follow the local custom of wife beating.
Mengele worked as a carpenter in Buenos Aires, Argentina, while lodging in a boarding house in the suburb of Vicente López.[67] After a few weeks he moved to the house of a Nazi sympathizer in the more affluent neighborhood of Florida Este. He next worked as a salesman for his family's farm equipment company, Karl Mengele & Sons, and in 1951 he began making frequent trips to Paraguay as regional sales representative.[68] He moved into an apartment in central Buenos Aires in 1953, he used family funds to buy a part interest in a carpentry concern, and he then rented a house in the suburb of Olivos in 1954.[69] Files released by the Argentine government in 1992 indicate that Mengele may have practiced medicine without a license while living in Buenos Aires, including performing abortions.[70]

In 1950, the Dutch translator Rosey E. Pool made a first translation of the Diary, which was never published.[26] At the end of 1950, another translator was found to produce an English-language version. Barbara Mooyaart-Doubleday was contracted by Vallentine Mitchell in England, and by the end of the following year, her translation was submitted, now including the deleted passages at Otto Frank's request. As well, Judith Jones, while working for the publisher Doubleday, read and recommended the Diary, pulling it out of the rejection pile.[27] Jones recalled that she came across Frank's work in a slush pile of material that had been rejected by other publishers; she was struck by a photograph of the girl on the cover of an advance copy of the French edition. "I read it all day", she noted. "When my boss returned, I told him, 'We have to publish this book.' He said, 'What? That book by that kid?'" She brought the diary to the attention of Doubleday's New York office. "I made the book quite important because I was so taken with it, and I felt it would have a real market in America. It's one of those seminal books that will never be forgotten", Jones said.[28] The book appeared in the United States and in the United Kingdom in 1952, becoming a best-seller. The introduction to the English publication was written by Eleanor Roosevelt.

How, when, and why the Nazis’ decision to exterminate Europe’s Jews was made remains one of the most vexed and disputed of all important questions concerning the Holocaust. There was not simply an order from Hitler commanding the killing of the Jews, and there is general agreement that the genocide evolved in stages, steadily becoming more comprehensive. The Origins of the Final Solution by the universally respected historian Christopher R. Browning, now at the University of North Carolina at Chapel Hill, is a magisterial examination of this subject in the wider context of the overall evolution of Nazi policy towards the Jews between the outbreak of the Second World War in September 1939 and the opening of the first extermination camps early in 1942.

Trainloads of human cargo arriving at Auschwitz went through a selection process conducted by SS doctors such as Josef Mengele. Young adults considered fit for slave labor were allowed to live and had an ID number tattooed on their left forearm. Everyone else went to the gas chambers. A few inmates, including twin children, were occasionally set aside for participation in human medical experiments.

The match was perfect. The video image of the photograph was imposed precisely over the video image of the skull. It was a face wrapped over a skull, subject over object, an image of life over an image of death. While the images helped to push the probability calculation further in the direction of a definitive identification, they did more than that, for it was the appearance of a previously unseen image that produced the potential for conviction.

Peter Hayes (How Was It Possible? A Holocaust Reader, 2015): "The Holocaust, the Nazi attempt to eradicate the Jews of Europe, has come to be regarded as the emblematic event of Twentieth Century ... Hitler's ideology depicted the Jews as uniquely dangerous to Germany and therefore uniquely destined to disappear completely from the Reich and all territories subordinate to it. The threat posted by supposedly corrupting but generally powerless Sinti and Roma was far less, and therefore addressed inconsistently in the Nazi realm. Gay men were defined as a problem only if they were German or having sex with Germans or having sex with Germans and considered 'curable' in most cases. ... Germany's murderous intent toward the handicapped inhabitants of European mental institutions ... was more comprehensive ... but here, too, implementation was uneven and life-saving exceptions permitted, especially in Western Europe. Not only were some Slavs—Slovaks, Croats, Bulgarians, some Ukrainians—allotted a favored place in Hitler's New Order, but the fate of most of the other Slavs the Nazis derided as sub-humans ... consisted of enslavement and gradual attrition, not the prompt massacre meted out to the Jews after 1941."[20]
But the diary in itself, richly crammed though it is with incident and passion, cannot count as Anne Frank’s story. A story may not be said to be a story if the end is missing. And because the end is missing, the story of Anne Frank in the fifty years since “The Diary of a Young Girl” was first published has been bowdlerized, distorted, transmuted, traduced, reduced; it has been infantilized, Americanized, homogenized, sentimentalized; falsified, kitschified, and, in fact, blatantly and arrogantly denied. Among the falsifiers have been dramatists and directors, translators and litigators, Anne Frank’s own father, and even—or especially—the public, both readers and theatregoers, all over the world. A deeply truth-telling work has been turned into an instrument of partial truth, surrogate truth, or anti-truth. The pure has been made impure—sometimes in the name of the reverse. Almost every hand that has approached the diary with the well-meaning intention of publicizing it has contributed to the subversion of history.

The number of Afro-Germans in Germany when the Nazis came to power is variously estimated at 5,000–25,000.[454] It is not clear whether these figures included Asians. Although blacks, including prisoners of war, in Germany and German-occupied Europe were subjected to incarceration, sterilization, murder, and other abuse, there was no programme to kill them all as there was for the Jews.[455]
The diary is not written in the classic forms of "Dear Diary" or as letters to oneself; Anne calls her diary "Kitty", so almost all of the letters are written to Kitty. Anne used the above-mentioned names for her annex-mates in the first volume, from September 25, 1942 until November 13, 1942, when the first notebook ends.[18] It is believed that these names were taken from characters found in a series of popular Dutch books written by Cissy van Marxveldt.[18]

Mengele joined the Nazi Party in 1937 and the Schutzstaffel (SS; protection squadron) in 1938. He received basic training in 1938 with the Gebirgsjäger (light infantry mountain troop) and was called up for service in the Wehrmacht (Nazi armed forces) in June 1940, some months after the outbreak of World War II. He soon volunteered for medical service in the Waffen-SS, the combat arm of the SS, where he served with the rank of SS-Untersturmführer (second lieutenant) in a medical reserve battalion until November 1940. He was next assigned to the SS-Rasse- und Siedlungshauptamt (SS Race and Settlement Main Office) in Poznań, evaluating candidates for Germanization.[18][19]