This introductory chapter provides an overview of the book's main themes. This book makes subject matter an independent factor in meaning, constrained but not determined by truth-conditions. A sentence's meaning is to do with its truth-value in various possible scenarios, and the factors responsible for that truth-value. No new machinery is required to accommodate this. The proposition that S is made up of the scenarios where S is true; S's reasons for, or ways of, being true are just additional propositions. When Frost writes, The world will end in fire or in ice, the truth-conditional meaning of his statement is an undifferentiated set of scenarios. Its “enhanced” meaning is the same set, subdivided into fiery-end worlds and icy-end worlds.