National Socialism grew out of many complex developments, of which the most influential were nationalism and racism. These two ideas captured the mind of the young Adolf Hitler (1889–1945), and he dominated Nazism until the end of World War II.

The son of an Austrian customs official, Hitler spent his childhood in small towns in Austria. After dropping out of school at age fourteen, Hitler moved to Vienna, where he was exposed to extreme Austro-German nationalists who advocated the union of Austria with Germany and the violent expulsion of “inferior” peoples as the means of maintaining German domination of the Austro-Hungarian Empire.

In Vienna, Hitler developed a belief in the crudest distortions of Social Darwinism (see "Darwin and Natural Selection" in Chapter 22), the superiority of Germanic races, and the inevitability of racial conflict. Exposure to poor eastern European Jews contributed to his anti-Semitic prejudice. Jews, Hitler now claimed, directed an international conspiracy of finance capitalism and Marxist socialism against German culture, German unity, and the German people.

Hitler was not alone. Racist anti-Semitism became wildly popular on the far right wing of European politics in the decades surrounding the First World War. Such irrational beliefs, rooted in centuries of Christian anti-Semitism, were given pseudoscientific legitimacy by nineteenth-century developments in biology and eugenics. These ideas came to define Hitler’s worldview and would play an immense role in the ideology and actions of National Socialism.

Hitler greeted the outbreak of the First World War as a salvation. The struggle and discipline of war gave life meaning, and Hitler served on the western front. Germany’s defeat shattered his world. Convinced that Jews and Marxists had “stabbed Germany in the back,” he vowed to fight on.

In late 1919, Hitler joined a tiny extremist group in Munich called the German Workers’ Party. By 1921, Hitler had gained control of this small but growing party, which had been renamed the National Socialist German Workers’ Party, or Nazis for short. In late 1923 the Weimar Republic seemed on the verge of collapse, and Hitler, inspired by Mussolini’s recent victory, organized an armed uprising in Munich — the so-called Beer Hall Putsch. Despite the failure of the poorly planned coup and Hitler’s arrest, National Socialism had been born.