The problem of universals, important in the history of philosophy, remains a crucial issue today not only for metaphysics, but also for the philosophy of science. This anthology offers a comprehensive presentation of twenty-eight analyses of the problem of universals. It opens with analyses presented by Plato and Aristotle and then provides selections from the views of the medieval scholars Abelard, Aquinas, Duns Scotus, and Ockham. It then traces the development of Western thought on this fundamental topic from the modern through the contemporary period and includes the work of Kant, Hegel, Husserl, Heidegger, Russell, Quine, Strawson, Carnap, and Allaire. To aid the student in understanding these investigations into the nature of universals, each reading is preceded by a concise introduction by the editor.