John Finnis has been a central figure in the fundamental re-shaping of legal philosophy over the past half-century. This volume of his Collected Essays shows the full range and power of his contributions to the philosophy of law. The volume collects nearly thirty papers: on the foundations of law's authority; major theories and theorists of law; legal reasoning; revolutions, rights and law; and the logic of law-making. The essays collected include Finnis' recent appreciations and root-and-branch critiques of Hart's legal and political theories, his engagements with other central figures and works in the field, including Dworkin's Law's Empire; Raz on authority and coordination; Coleman, Leiter and Gardner on legal positivism and naturalism; Aquinas as founder of legal positivism; Weber on the fact-value distinction and legitimation; Unger on indeterminacy in law; Posner on intention and economics; Kelsen and courts on revolutions; game-theory and rational-choice theory; with misinterpreters of Hohfeld on rights logic; John Paul II on voting for unjust laws; analogy's role in legal reasoning; the distribution of constitutional authority in the Empire and its dissolution; the judicial opportunism of separation of powers doctrine in the Australian constitution; the architecture of Blackstone's Commentaries; restitution in civil wrongs; and many other aspects of law and legal theory. Several papers bring to bear his extensive work as a constitutional adviser and lawyer on persistent problems of constitutional theory.Previously unpublished papers include two on critical or post-modern legal theory, and an introduction reflecting on legal philosophy's development and future.