The Concept of Mind is a 1949 book by philosopher Gilbert Ryle, in which Ryle argues that "mind" is "a philosophical illusion hailing chiefly from René Descartes and sustained by logical errors and 'category mistakes' which have become habitual." The work has been cited as having "put the final nail in the coffin of Cartesian dualism" and has been seen as a founding document in the philosophy of mind, which received professional recognition as a distinct and important branch of philosophy only after 1950.