In the mid-1990s, Klaus-Michael Mallmann published his study on 'Communists in the Weimar Republic'. His newly established social-historical approach on the Communist Party of Germany (KPD) has since been taken up by other historians. One of them is Christian Gotthardt, who recently published a book with the promising title 'The Radical Left as a Mass Movement'. Here he focuses on the regional history of the KPD in the city of Harburg-Wilhelmsburg. The great strength of his book is the detailed description of the local Communists' day-to-day work. However, when turning his attention to the turning points of KPD history, the problems associated with adopting Mallman's social-historical approach become obvious. For example this leads them both to reject the theory of 'Stalinisation'. The article shows that Gotthardt, as well as Mallmann, had come to questionable conclusions on the development of the KPD of the Weimar Republic by focusing on events outside of their context in time and space.