This volume documents the 16th Munster Lectures in Philosophy and examines five themes that are prominent in the work of philosopher and political theorist Philip Pettit. These themes are: Epistemology and Semantics, Philosophy of Mind, Consequentialism, Group Agency, and Republicanism. The book provides insight into Pettit’s work and demonstrates the central role his work plays in a number of contemporary philosophical debates. Pettit’s contributions to the philosophy of mind and action, rational choice theory, the philosophy of the social sciences, as well as metaethics, normative ethics and political philosophy are main points of reference, and have advanced ongoing and initiated new discussions. The book shows that a striking feature of Pettit’s work has been the depth of his analyses and arguments regarding individual topics - ranging from rule-following to free will, from group agency to social ontology and the methodology of the social sciences, from a defense of consequentialism to the revival of the republican tradition in the theory of democracy and to value theory, but also their systematic overall coherence. The book contains Pettit’s lecture Freedom and Other Robustly Demanding Goods , nine critical papers on Pettit’s philosophy, and a reply article entitled Self-Defense on Five Fronts: A Reply to My Commentators .