Renn's growing commitment to communism saw him travel to the USSR in 1929 and 1930. Renn found himself increasingly under attack from the National Socialists and decided to renounce his noble title in 1930, adopting the name of the protagonist of his novel, "Krieg": Ludwig Renn. Between 1931 and 1932 he was a lecturer on the history of warfare and military theory at the Marxist Workers’ School (MASCH) in Berlin. His books "Nachkrieg" (1930) and "Rußlandfahrten" (1932) made him the most important German communist writer of the inter-war period.