Medieval logic is usually divided into the branches that derived from Aristotle's organon - the 'logica vetus' and 'logica nova', and those invented in the Middle Ages, the 'logica modernorum'. In this volume, a group of distinguished specialists asks whether the ancient roots of medieval logic were not in fact more varied. Stoic logic was mostly lost, but were some of its themes transmitted, even in distorted form, through Boethius and through the grammatical tradition? And did other schools, such as the sceptics and the Platonists, contribute in their own ways to medieval logic?