Christine M. Korsgaard has had a profound influence on moral philosophy over the past forty years. Through her writing and teaching she has developed a distinctive, rigorous, and historically informed way of thinking about ethics, agency, and the normative dimension of human life more generally. The twelve original essays in this volume are written in her honor on the occasion of her retirement from teaching. They engage questions that recur in her work: Why are we obligated to do what morality demands? What features of our nature make us subject to moral obligation? What does it mean to be autonomous and responsible for what we do? What do we owe to nonhuman animals? Contributors include Stephen Darwall, Kyla Ebels-Duggan, Barbara Herman, Richard Moran, Japa Pallikkathayil, Faviola Rivera-Castro, T.M. Scanlon, Tamar Schapiro, Sharon Street, David Sussman, Sigrún Svavarsdóttir, and David Velleman. These essays shed light on Korsgaard's own views while staking out provocative new positions on the topics that feature centrally in her own work.