Adolf Hitler was the Nazi leader and German Chancellor from 1933 to 1945, known for his role in World War II and the Holocaust. Key historical events include the Beer Hall Putsch in 1923, his book 'Mein Kampf' published in 1924, and his foreign policy objectives which aimed to dismantle the Treaty of Versailles, unify German-speaking peoples, and expand German territory. Hitler is held responsible for Germany's military defeat in World War II and the deaths of millions of people.