G.P.Baker was a Fellow of St John?s College, Oxford from 1967 until his death in 2002. He is the co-author with P.M.S. Hacker of the first two volumes of the four-volume Analytical Commentary on the Philosophical Investigations (Blackwell, 1980?96), and with Katherine Morris of Descartes? Dualism (1996). He also wrote numerous articles on Wittgenstein, Frege, Russell, Waismann and Descartes. P.M.S. Hacker is the leading authority on the philosophy of Wittgenstein. He is author of the four-volume Analytical Commentary on the Philosophical Investigations, the first two volumes co-authored with G.P. Baker (Blackwell, 1980?96) and of Wittgenstein?s Place in Twentieth-century Analytic Philosophy (Blackwell, 1996). He has also written extensively on philosophy of language and philosophy of mind, most recently The Philosophical Foundations of Neuroscience (Blackwell, 2003), co-authored with M.R. Bennett.