To mark the birthday of David below is a relatively recent and welcome return by him to metaphysics after moving away, primarily to ethics, for the latter part of his career. Sameness and Substance would figure in my top twenty favourite philosophical books, historical or contemporary, and one of a handful of direct influences upon my technical writing. I had the privilege of being one of his students for ethics but as it happens at that time he’d moved away from metaphysics. David is a very kind, gentle, low-key and equitable man who went into bat for me and other students I knew. David is a philosopher’s philosopher as one would say, something that is sadly unfashionable these days.