Cicero's general interest in Dicaearchus' ethical and political thought can be detected in his letters to Atticus and De legibus. At present, however, we do not possess a clear and detailed picture of Dicaearchus' influence on Cicero's own ethical and political thought. This chapter argues that, despite these obstacles, we can construct a positive account of the nature and extent of Dicaearchus' influence that offers new insights into key aspects of Cicero's philosophical thought and practice. First it offers a novel reconstruction of Dicaearchus' argument for the supremacy of the praktikos bios and his relationship with Aristotle and Theophrastus in the Peripatetic tradition. The chapter then considers how Dicaearchus figures in Cicero's p...