In 1913, Lukács began participating in the influential “Sunday circle” of Budapest intellectuals, which included Karl Mannheim. After returning from wartime service in the Hungarian censor’s office, he published The Theory of the Novel (1916), which is perhaps the best-known work of his early period. In 1917, he left Grabenko and, despite Weber’s support, failed to receive the Habilitation (teaching qualification) at the University of Heidelberg. Between 1916 and 1918 he also resumed his work on aesthetics, resulting in the unpublished manuscript of the so-called “Heidelberg Aesthetics” (GW 17). To the surprise of many of his friends, Lukács joined the Hungarian Communist Party in 1918; although, as his essay on “Bolshevism as a Moral Problem” attests, not without reservations.