In 1928, the year in which he published "Krieg", Renn became a member of the German Communist Party, a step which the novel "Nachkrieg" (1930) reflects. In the same year he joined the Roter Frontkämpferbund (‘Alliance of Red Front-Fighters’) and from 1928 to 1932 was secretary of the Alliance of Proletarian-Revolutionary Writers in Berlin (BPRS). Renn was editor of the communist journal, "Linkskurve" and the communist military police journal, "Aufbruch". His work for the BPRS brought him into close contact with, amongst others, Anna Seghers and Johannes R Becher.