After his attempted putsch on November 9, 1923, whereupon he was sentenced as a traitor, Hitler found the time to write Mein Kampf. In an interview in July 1924, he pointed out that the process of writing the book made him aware that he had previously been much too liberal toward Judaism. He stated that he planned to “employ the strongest of weapons” in the future. This article explores the questions of when Hitler’s racist anti-Semitism began, what part Mein Kampf played in this development, and how Hitler’s anti-Semitism subsequently became increasingly radical.