This work investigates how ancient philosophers understood productive knowledge or techne and used it to explain ethics, rhetoric, politics and cosmology. In eleven chapters leading scholars set out the ancient debates about techne from the Presocratic and Hippocratic writers, through Plato and Aristotle and the Hellenistic age (Stoics, Epicureans and Sceptics), ending in the Neoplatonism of Plotinus and Proclus. Amongst the many themes that come into focus are: the model status of ancient medicine in defining the political art, the similarities between the Platonic and Aristotelian conceptions of techne, the use of techne as a paradigm for virtue and practical rationality, technes determining role in Platonic conceptions of cosmology, technes relationship to experience and theoretical knowledge, virtue as an 'art of living', the adaptability of the criteria of techne to suit different skills, including philosophy itself, the use in productive knowledge of models, deliberation, conjecture and imagination.