The Moral Universe explores central questions in metaethics concerning the nature of moral reality, its fundamental laws, its relation to the natural world, and its normative authority. It employs a novel philosophical method to offer the most sustained and sophisticated development of nonnatural moral realism to date. The authors advance new ways of answering these questions, contending that moral standards regarding what to do and how to be are not only objectively authoritative, but essentially so. Rather than arising from personal schemes or collective ideals, morality flows from the nature of things. One of the principal aims of the book is to show how this view accommodates and explains a wide range of data concerning the metaphysical and normative dimensions of morality. Along the way, the book offers novel characterizations of moral realism and nonnaturalism, defends and explains the existence of substantive moral conceptual truths, supplies a new treatment of moral supervenience, substantiates the categoricity and importance of moral reasons, and presents a strategy for identifying the source of morality. Exemplifying a commitment to the integrity of moral philosophy, The Moral Universe also tackles fundamental issues in value theory and normative ethics in the service of developing a systematic, explanatorily potent version of nonnaturalist realism.