 Thomas Hill Green (1836–82) was the first of the great Oxford idealists. He is best remembered for a lengthy polemic with Hume that he published in the form of an introduction to a collected edition of Hume that he co-edited and for his posthumously published Prolegomena to Ethics, which is a polemic against utilitarianism from the point of view of a perfectionism inspired by Kant as well as by Hegel. But the first of the four books of the Prolegomena is a “Metaphysics of Knowledge”, beginning with a statement of “The Spiritual Principle in Knowledge and in Nature” (1893: 13), which argues for a form of idealism on both epistemological and ontological grounds, and Green’s posthumous works also included a set of lectures on Kant in which he engaged quite directly with Kant’s form of idealism. Green also left behind a set of Lectures on the Principles of Political Obligation that form one of the crucial documents of the political and social philosophy of British idealism and of idealism in the broadest sense mentioned at the outset of this entry.