 Recent scholarship has also helped remind readers of the influence Russell’s students had on Russell’s philosophy.  Ludwig Wittgenstein  and Frank Ramsey especially presented Russell with helpful criticisms of his work and new problems to solve. Both men pushed Russell to develop new theories in logic and epistemology. Despite the fact that Wittgenstein was less than satisfied with Russell’s Introduction to his Tractatus Logico-Philosophicus (1921), Michael Potter’s Wittgenstein’s Notes on Logic (2009) and the introductory materials published in Russell’s Theory of Knowledge: The 1913 Manuscript (CP, Vol. 7) show the extent and fruitfulness of the interaction between teacher and student. 