We commonly believe that communication is successful when a hearer grasps what a speaker means. But Abe can assert “Sam is tall” without having any definite intention about how tall one must be to count as “tall,” and Bertha can understand his assertion without grasping such an intention. What exactly has been communicated in such a case? John MacFarlane argues that standard models of meaning and communication cannot answer this question. To answer it, he proposes, we need to see vague talk as not purely factual but in part expressive of linguistic plans. In this book, he gives a novel expressivist account of vagueness and explores its implications for semantics, pragmatics, thought, and disagreement.