This book expounds and defends a new conception of the relation between truth and meaning. Atlas argues that the sense of a sense-general sentence radically underdetermines (independently of indexicality) its truth-conditional content. He applies this linguistic analysis to illuminate old and new philosophical problems of meaning, truth, falsity, negation, existence, presupposition, and implicature. In particular, he demonstrates how the concept of ambiguity has been misused and confused with other concepts of meaning, and how the interface between semantics and pragmatics has been misunderstood. The problems he tackles are common to philosophy, linguistics, cognitive psychology, and artificial intelligence, and his conclusions will be of interest to all those working in these fields.