This chapter introduces and motivates the compositionality requirement on natural language semantics. It argues that quantifying over meanings is neither necessary nor sufficient for meeting this requirement. It introduces Tarski's Convention T and explains how it gives rise to the proposal to use a truth theory to give a meaning theory. It illustrates the basic approach first with a simple context-insensitive language and then with a context-sensitive language. Finally, it gives an explicit statement of the form of a meaning theory, and draws out some of its consequences in responding to some objections.
Keywords: compositionality, Tarski, Convention T, truth theory, meaning theory