Cicero's De finibus, written in 45 BC, consists of three separate dialogues, dealing respectively with the ethical systems of Epicureanism, Stoicism, and the 'Old Academy' of Antiochus of Ascalon. An encyclopaedic survey of this nature is of particular importance for its detailed account of Stoic ethics. This critical edition of the text, based on a fresh study and collation of the manuscripts, is the first to appear for many years and the first to reflect a clear understanding of the whole manuscript tradition.