For more than forty years Gilbert Ryle has been a unique figure on the skyline of British philosophy, and for at least half that time an influential one. No philosopher since James has written in such a vivid, racy, down-to-earth style. No philosopher since Russell in his heyday has used epigrams and sallies more devastatingly to expose “grave conceptual bosh.” Little wonder then, that for large numbers of students Ryle is a delight to read, or that many of his coinages are a familiar part of the currency of our era (“categorymistake,” “privileged access,” “the ghost in the machine,” etc.). Yet his philosophical influence comes, I think, not from the charms of his person or his style, but from the vigour of his ideas and arguments. Whether he is unravelling a particular knot of problems, as in The Concept of Mind, or dealing with a whole series of problems, as in these Collected Papers, his ideas and arguments rarely fail to stimulate and provoke. I cannot imagine how anyone could study Ryle and remain intellectually motionless. Moreover, just because the pieces reprinted here have such an impressive range, they set off motions along a multitude of fronts, even in the case of those who have read the pieces before. Their publication is thus a most welcome philosophical event.