In this definitive new en face German-English edition, Wittgenstein experts Peter Hacker and Joachim Schulte have incorporated significant editorial changes to earlier editions of Philosophical Investigations in order to reflect more closely Wittgenstein´s original intentions. Notable revisions include the placement of Wittgenstein´s notes - Randbemerkungen - into their designated positions in the text, some corrections to the originally published German text, and the numbering of all the remarks in what was Part 2 and is now named Philosophy of Psychology - A Fragment.