This book reconstructs the theory of signification implicit in Aristotle’s De Interpretatione and its psychological background in hisDe Anima. The study develops in three steps that correspond to the three elements involved in every notion of signification: (1) the phonetic element or significans, called phônê by Aristotle, (2) the significatum, i. e. what the phonetic material stands for, and (3) the relation between significans and significatum. This work breaks new ground by connecting the linguistic and psychological aspects of Aristotle’s theory of signification.