Originally published in 1925, Mein Kampf is largely predicated on Hitler's allegation of the existence of a massive Jewish conspiracy against the German people. After Hitler assumed absolute power in 1933, the Nazis enacted a series of laws meant to segregate and otherwise dehumanize the Jews. Kristallnacht, known as the Night of Broken Glass, was an organized nationwide pogrom that took place in 1938. By this point, all German Jews -- even those who had fought for Germany in World War I -- had been stripped of their rights as citizens and formally excluded from German society.
Hitler maintained his intention of eliminating Jews from Germany and, later, Germany's conquered possessions. In the initial stages of this process, German Jews were terrorized into emigrating; those who remained were ultimately rounded up and forced into concentration camps and labor camps. Jews were joined by homosexuals, gypsies, dissidents, Communists, and Polish and Soviet prisoners of war. Many prisoners engaged in forced labor for German corporations and armament factories, thus contributing to the war effort of the nation that condemned them. The infamous gas chambers at Auschwitz began operation in 1942; from that point on, captured and deported Jews were primarily sent straight to extermination camps, complexes built for the express purpose of efficiently and regularly murdering large numbers of people.
In 1933, the first concentration camp was established at Dachau in southeast Germany, outside the large city of Munich. The longest running Nazi concentration camp in continual operation, Dachau was not an extermination camp per se, yet tens of thousands of Jews and other prisoners died there; countless more were transferred from Dachau to actual extermination camps. Dachau was liberated by the United States Army in 1945 just a few weeks before Germany's surrender.
About six million Jews died in the Holocaust. Millions more -- members of other groups targeted for extermination by the Nazis in Hitler's quest for racial purity and world conquest -- perished as well. Up to 10% of Germany's population, civilians and soldiers, are estimated to have perished in Hitler's war.