The diary has been praised for its literary merits. Commenting on Anne Frank's writing style, the dramatist Meyer Levin commended Frank for "sustaining the tension of a well-constructed novel",[78] and was so impressed by the quality of her work that he collaborated with Otto Frank on a dramatization of the diary shortly after its publication.[79] Levin became obsessed with Anne Frank, which he wrote about in his autobiography The Obsession. The poet John Berryman called the book a unique depiction, not merely of adolescence but of the "conversion of a child into a person as it is happening in a precise, confident, economical style stunning in its honesty".[80]
Following the camp's liberation, the Soviet government issued a statement, on 8 May 1945, that four million people had been killed on the site, a figure based on the capacity of the crematoria and later regarded as too high.[185] Höss told prosecutors at Nuremberg that at least 2,500,000 people had been murdered in Auschwitz by gassing and burning, and that another 500,000 had died of starvation and disease.[186] He testified that the figure of over two million had come from Eichmann.[187][d] In his memoirs, written in custody, he wrote that he regarded this figure as "far too high. Even Auschwitz had limits to its destructive possibilities."[189] Raul Hilberg's 1961 work, The Destruction of the European Jews, estimated that up to 1,000,000 Jews had died in Auschwitz.[190]

The general membership of the Nazi Party mainly consisted of the urban and rural lower middle classes. 7% belonged to the upper class, another 7% were peasants, 35% were industrial workers and 51% were what can be described as middle class. In early 1933, just before Hitler's appointment to the chancellorship, the party showed an under-representation of "workers", who made up 29.7% of the membership but 46.3% of German society. Conversely, white-collar employees (18.6% of members and 12% of Germans), the self-employed (19.8% of members and 9.6% of Germans) and civil servants (15.2% of members and 4.8% of the German population) had joined in proportions greater than their share of the general population.[115] These members were affiliated with local branches of the party, of which there were 1,378 throughout the country in 1928. In 1932, the number had risen to 11,845, reflecting the party's growth in this period.[115]
The Communist Party of Germany (KPD) was the largest Communist Party in the world outside of the Soviet Union, until it was destroyed by the Nazis in 1933.[256] In the 1920s and early 30s, Communists and Nazis often fought each other directly in street violence, with the Nazi paramilitary organizations being opposed by the Communist Red Front and Anti-Fascist Action. After the beginning of the Great Depression, both Communists and Nazis saw their share of the vote increase. However, while the Nazis were willing to form alliances with other parties of the right, the Communists refused to form an alliance with the Social Democratic Party of Germany, the largest party of the left.[257] After the Nazis came to power, they quickly banned the Communist Party under the allegation that it was preparing for revolution and that it had caused the Reichstag fire.[258] Four thousand KPD officials were arrested in February 1933, and by the end of the year 130,000 communists had been sent to concentration camps.[259]
But individual deaths, by sickness or violence, were not enough to keep the number of prisoners within manageable limits. Accordingly, in early 1941 Himmler decided to begin the mass murder of prisoners in gas chambers, building on a program that the Nazis had developed earlier for euthanizing the disabled. Here, again, the camps’ sinister combination of bureaucratic rationalism and anarchic violence was on display. During the following months, teams of S.S. doctors visited the major camps in turn, inspecting prisoners in order to select the “infirm” for gassing. Everything was done with an appearance of medical rigor. The doctors filled out a form for each inmate, with headings for “Diagnosis” and “Incurable Physical Ailments.” But it was all mere theatre. Helm’s description of the visit of Dr. Friedrich Mennecke to Ravensbrück, in November, 1941, shows that inspections of prisoners—whom he referred to in letters home as “forms” or “portions”—were cursory at best, with the victims parading naked in front of the doctors at a distance of twenty feet. (Jewish prisoners were automatically “selected,” without an examination.) In one letter, Mennecke brags of having disposed of fifty-six “forms” before noon. Those selected were taken to an undisclosed location for gassing; their fate became clear to the remaining Ravensbrück prisoners when the dead women’s clothes and personal effects arrived back at the camp by truck.
In Mein Kampf, Hitler stated that Lebensraum would be acquired in Eastern Europe, especially Russia.[132] In his early years as the Nazi leader, Hitler had claimed that he would be willing to accept friendly relations with Russia on the tactical condition that Russia agree to return to the borders established by the German–Russian peace agreement of the Treaty of Brest-Litovsk signed by Vladimir Lenin of the Russian Soviet Federated Socialist Republic in 1918 which gave large territories held by Russia to German control in exchange for peace.[131] In 1921, Hitler had commended the Treaty of Brest-Litovsk as opening the possibility for restoration of relations between Germany and Russia by saying:

Between 1939 and 1945, the Nazi Party led regime, assisted by collaborationist governments and recruits from occupied countries, was responsible for the deaths of at least eleven million people,[94][95] including 5.5 to 6 million Jews (representing two-thirds of the Jewish population of Europe),[11][96][97] and between 200,000 and 1,500,000 Romani people.[98][99] The estimated total number includes the killing of nearly two million non-Jewish Poles,[100] over three million Soviet prisoners of war,[101] communists, and other political opponents, homosexuals, the physically and mentally disabled.[102][103]
From the first escape on 6 July 1940 of Tadeusz Wiejowski,[216] at least 802 prisoners (757 men and 45 women) tried to escape from the camp, according to Polish historian Henryk Świebocki. He writes that most escapes were attempted from work sites outside the camp.[217][f] Of these, 144 were successful and the fate of 331 is unknown.[218] Four Polish prisoners—Eugeniusz Bendera (a car mechanic at the camp), Kazimierz Piechowski, Stanisław Gustaw Jaster, and a priest, Józef Lempart—escaped successfully on 20 June 1942.[219] After breaking into a warehouse, the four dressed as members of the SS-Totenkopfverbände (the SS units responsible for concentration camps), armed themselves, and stole an SS staff car, which they drove unchallenged through the main gate, greeting several officers with "Heil Hitler!" as they drove past.[220] On 21 July 1944, Polish inmate Jerzy Bielecki dressed in an SS uniform and, using a faked pass, managed to cross the camp's gate with his Jewish girlfriend, Cyla Cybulska (known as Cyla Stawiska), pretending that she was wanted for questioning. Both survived the war. For having saved her, Bielecki was recognized by Yad Vashem as Righteous Among the Nations.[221]

Heinrich Himmler's Schutzstaffel (SS) took full control of the police and the concentration camps throughout Germany in 1934–35.[5] Himmler expanded the role of the camps to hold so-called "racially undesirable elements", such as Jews, Gypsies/Romanis/Sintis, Serbs, Poles, disabled people, and criminals.[6][7][8] The number of people in the camps, which had fallen to 7,500, grew again to 21,000 by the start of World War II[9] and peaked at 715,000 in January 1945.[10]