 Friedrich Albert Lange is a figure whose influence and thought remains to be judged accurately, especially in the Anglophone tradition. His influence as a teacher and as a mentor was as strong as were his more public intellectual contributions. The positions Lange carved out were not merely a response to nineteenth century intellectual movements including neo-Kantianism, materialism, Marxism, and Darwinism, though they were regarded widely as effective responses. Lange conceived independent and influential positions in logic, in national economy, in pedagogy, and in epistemology. He did so while pursuing a career as an activist and social organizer. His place in the history of philosophy, of politics, and of science remains to be established by future scholarship.