The Holocaust was the systematic and bureaucratic annihilation of six million Jews as well as other "undesirables" by the Nazi regime and their collaborators as a central act of state during World War II. The Holocaust took place in Europe from January 30, 1933, when Hitler became Chancellor of Germany, to May 8, 1945 when the war ended in Europe.

The European Jews were the primary victims of the Holocaust—up to two out of every three Jews in Europe were killed. Jews, however, were certainly not the only group singled out for persecution by Hitler’s regime. As many as one-half million Gypsies, at least 250,000 mentally or physically disabled persons, and more than three million Soviet prisoners-of-war also fell victim to Nazi genocide. Jehovah’s Witnesses, homosexuals, Social Democrats, Communists, partisans, Polish intelligentsia and other "undesirables" were also victims of the hate and aggression carried out by the Nazis.

While it is impossible to ascertain the exact number of victims, statistics indicate that the total number of Jews murdered was over 5,830,000. Six million Jewish victims is the round figure accepted by most authorities.  There were many millions of additional victims, including Communists, trade unionists, Socialists, Roma and Sinti (Gypsies), Jehova's Witnesses, Soviet citizens, Soviet prisoners of war, and homosexuals.

"Nazi" is a term used for members of the National Socialist German Workers Party (NSDAP). This right-wing political party was formed primarily by unemployed German veterans of World War I in 1919, just after the end of the war and Germany’s defeat. In 1921 Adolph Hitler became the head of the party, and the Nazis slowly became a powerful political force under his leadership. The Nazi Party ideology was largely based on nationalism and racism. They promoted Germany as superior to all other nations and promised to restore it to greatness, while championing a scientific "theory" of racism, in which the "Aryan" (German) people were racially superior to all others, especially the "mongrel" race of the Jews.

Immediately following the Nuremberg Laws in 1935, the Nazis issued the official definition of a Jew. According to German law, anyone with three Jewish grandparents was a Jew. In addition, anyone married to a Jewish person or who had one Jewish parent was also considered a Jew in the eyes of the law.

Those not classified as Jews under German law, but had some "Jewish blood," were categorized as Mischlinge, or hybrids. Those with two Jewish grandparents were to be known as Mischlinge of the first degree, while those with one Jewish grandparent were of the second degree. In short, Judaism for the Nazis was something racial, something someone was born into and about which they could do nothing.

A death camp, or extermination camp, was a concentration camp with special apparatus especially designed for mass murder, like gas chambers. Six such camps existed: Auschwitz-Birkenau, Belzec, Chelmno, Majdanek, Sobibor, and Treblinka. All were located in Poland.

The first concentration camp established was Dachau, which was opened on March 20, 1933. The camp’s first inmates were primarily political prisoners (most of whom were either Communists or Social Democrats), habitual criminals, homosexuals, Jehovah’s Witnesses, and anti-socials (beggars and vagrants). The camp also housed those considered problematic by the Nazis such as Jewish writers and journalists, lawyers, unpopular industrialists and officials.

The following were considered enemies of the Third Reich, and, therefore, were persecuted by Nazi authorities: Jews, Communists, Social Democrats, other opposing politicians, opponents of Nazism, Jehovah’s Witnesses, homosexuals, habitual criminals, anti-socials, the mentally ill, and anyone considered a threat to the Nazis.

The explanation of the Nazis’ implacable hatred for the Jews rests in their distorted world view that saw history as a racial struggle. They considered the Jews a race whose goal was world domination and, therefore, was an obstruction to Aryan dominance. They believed this struggle would resolve itself with the Aryans in control. Moreover, in their eyes, the Jews’ racial origin made them habitual criminals who could never be rehabilitated and were hopelessly corrupt and inferior. There is no doubt that other factors contributed to the Nazis’ hatred of the Jews and their distorted image of Jewish people. Among them were the centuries-old tradition of Christian anti-Semitism, which propagated a negative stereotype of the Jew as a Christ-killer, agent of the devil, and practitioner of witchcraft. Anti-Semitism was still accepted in the latter half of the nineteenth and early part of the twentieth century. This attitude singled out the Jew as a threat to the "master" race. These factors combined to point to the Jew as a target for persecution by the Nazis.