Introduction: authorship and authority in ancient philosophy Jenny Bryan, Robert Wardy and James Warren; 1. Reconsidering the authority of Parmenides' Doxa Jenny Bryan; 2. Authority and the dialectic of Socrates Nicholas Denyer; 3. Socratic discussions of death and immortality in Plato Alex Long; 4. A superannuated student: Aristotle and authority in the Academy Dorothea Frede; 5. Words, deeds, and lovers of truth in Aristotle Sarah Broadie; 6. Aristotle's Categories 7 adopts Plato's view of relativity Matthew Duncombe; 7. Theophrastus and the authority of the de Sensibus Kelli Rudolph; 8. Pseudo-Archytas and the Categories Myrto Hatzimichali; 9. Numenius on intellect, soul, and the authority of Plato George Boys-Stones; 10. Demetrius of Laconia on Epicurus On the Telos (Us. 68) James Warren; 11. Lucretius the madman on the gods David Butterfield; 12. In and out of the Stoa: Diogenes Laertius on Zeno A. A. Long; 13. The emergence of Platonic and Aristotelian authority in the First Century BCE Georgia Tsouni; 14. Cicero on auctoritas Malcolm Schofield; 15. Authors and authorities in ancient China: some comparative observations G. E. R. Lloyd; 16. Antique authority? Robert Wardy.