The writings preserved in Wittgenstein's manuscripts from 1945 to 1949, after he had completed the first part of Philosophical Investigations, chiefly concern the nature of certain psychological concepts. In this book Joachim Schulte uses these manuscripts - not the selections from them published so far - as a basis for reconstructing the central arguments and conceptual elucidations developed by Wittgenstein during that period. One of the principal subjects is the connection between instinctive reactions, linguistic and non-linguistic context, and mastery of a technique. This connection is explored through clarification of the concepts experience, sensation, and understanding - a clarification which provides illuminating contributions to the philosophy of psychology, aesthetics, and the theory of meaning. Wittgenstein's thoughts on the logic of language and his reflections on psychological concepts are closely knit. This is shown by his discussion of Moore's paradox, which sheds new light both on the limits of logical analysis and on certain curious features of the concepts believe, assume, and assert. The original German edition of this book was widely applauded as an outstanding work of scholarship offering unique and valuable insights. By translating it into fluent and limpid English, and at the same time enriching it with various amendments and additions, Dr Schulte has brought an important work to a wider scholarly community.