Book excerpt: John MacFarlane debates how we might make sense of the idea that truth is relative, and how we might use this idea to give satisfying accounts of parts of our thought and talk that have resisted traditional methods of analysis. Although there is a substantial philosophical literature on relativism about truth, going back to Plato's Theaetetus, this literature (both pro and con) has tended to focus on refutations of the doctrine, or refutations of these refutations, at the expense of saying clearly what the doctrine is. In contrast, Assessment Sensitivity begins with a clear account of what it is to be a relativist about truth, and uses this view to give satisfying accounts of what we mean when we talk about what is tasty, what we know, what will happen, what might be the case, and what we ought to do. The book seeks to provide a richer framework for the description of linguistic practices than standard truth-conditional semantics affords: one that allows not just standard contextual sensitivity (sensitivity to features of the context in which an expression is used), but assessment sensitivity (sensitivity to features of the context from which a use of an expression is assessed). The Context and Content series is a forum for outstanding original research at the intersection of philosophy, linguistics, and cognitive science. The general editor is Francois Recanati (Institut Jean-Nicod, Paris).