In the last years of his life, from 1949 to 1951, Wittgenstein's writings focused upon knowledge and certainty (collected together in On Certainty), upon colour concepts (in Remarks on Colour) and upon the relation between the "inner" and "outer", that is, between so-called mental states and bodily behavior. His writings on this third theme, now available in paperback, are gathered here for the first time. Wittgenstein's last weeks were a period of high creativity during which his thoughts were on a level with the best he ever produced. His variation on the classic philosophical theme of the relation between mind and body is no exception.