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.