Hermann Ludwig Rudolph Duncker was a German Marxist politician, historian and social scientist. He was a lecturer for the workers' education movement, co-founder of the Communist Party of Germany, professor at the University of Rostock, and rector of East Germany's trade union academy.

The Communist Party of Germany was a major far-left political party in the Weimar Republic during the interwar period, an underground resistance movement in Nazi Germany, and a minor party in West Germany during the postwar period until it was banned by the Federal Constitutional Court in 1956.