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 Philosophical Foundations of Neuroscience (Blackwell, 2003) and History of Cognitive Neuroscience (Wiley-Blackwell, 2008), both co-authored with M. R. Bennett. He is also co-editor (with Joachim Schulte) and co-translator of the 4th edition of Wittgenstein's Philosophical Investigations (Wiley-Blackwell, 2009).