The Range of Reasons contributes to two debates by bringing them together. The first is a debate in metaethics concerning normative reasons, the considerations that serve to justify a person's actions and attitudes. The second is a debate in epistemology concerning the norms for belief, the standards that govern a person's beliefs and by reference to which they are assessed. The book begins by developing and defending a new theory of reasons for action; that is, of practical reasons. The theory belongs to a family that analyses reasons by appeal to the normative notion of rightness (fittingness, correctness). It is distinctive in making central appeal to modal notions, specifically that of a nearby possible world. The result is a comprehensive framework that captures what is common to and distinctive of reasons of various kinds: justifying and demanding; for and against, possessed and unpossessed; objective and subjective. The framework is then generalized to reasons for belief (epistemic reasons) and combined with a substantive, first-order commitment, namely that truth is the sole right-maker for belief. The upshot is an account of the various norms governing belief, including knowledge and rationality, the relations among them, and the unifying principle that underlies them all.