This article offers a comparative study of seven German biographies of Karl Marx (1818–1883) that were published between the two world wars. The interpretations of Marx’s theory of historical materialism presented in these biographies fall into three groups or approaches: the orthodox, the neo-Kantian, and the psychological. Some biographies place Marx the revolutionary above Marx the theorist, while others reverse this order. Similarly, some of the biographies explain the relationship between Marx’s life and thought by adopting the “experience–psychology–thought” framework. The (...) orthodox approach emphasizes the objectivity of cognition in the base–superstructure relationship. Yet both the orthodox and the neo-Kantian approach, which stresses Kant’s cognitive critique and the “is–ought” dualism, fail to grasp Marx’s subject–object dialectics, while the psychological approach undermines the theoretical significance of historical materialism. In comparing and assessing these works I argue that the biographers’ historical and scholarly horizons are dictated by their political standpoint and academic perspective and thus determine their choice of approach, which not only indicates if they will lean toward the theoretical or the revolutionary Marx, but also why they fail to adequately deal with the relationship between Marx’s life and his thought. Nevertheless, I conclude that these biographies, despite their various shortcomings, establish the basic paradigm and parameters of any biography of Marx. (shrink)