In 1919 Hess enrolled in the University of Munich, where he studied geopolitics under Karl Haushofer, a proponent of the concept of Lebensraum ("living space"), which became one of the pillars of Nazi ideology. Hess joined the NSDAP on 1 July 1920 and was at Hitler's side on 8 November 1923 for the Beer Hall Putsch, a failed Nazi attempt to seize control of the government of Bavaria. While serving time in jail for this attempted coup, he assisted Hitler with Mein Kampf, which became a foundation of the political platform of the NSDAP.