This is a new edition of the first volume of G.P.Baker and P.M.S. Hacker’s definitive reference work on Wittgenstein’s Philosophical Investigations.

- Takes into account much material that was unavailable when the first edition was written.

- Following Baker's death in 2002, P.M.S. Hacker has thoroughly revised the first volume, rewriting many essays and sections of exegesis completely.

- Part One – the Essays – now includes two completely new essays: 'Meaning and Use' and 'The Recantation of a Metaphysician'.

- Part Two – Exegesis §§1–184 – has been thoroughly revised in the light of the electronic publication of Wittgenstein's Nachlass, and includes many new interpretations of the remarks, a history of the composition of the book, and an overview of its structure.

- The revisions will ensure that this remains the definitive reference work on Wittgenstein’s masterpiece for the foreseeable future.