The Plutarchan De musica is an invaluable source of information on ancient Greek music. This new critical text, which is published more than 50 years after the edition of Konrat Ziegler, draws on a new examination of all the extant medieval and humanist manuscripts. All the emendations and conjectures proposed since the first printed edition (Venice 1509) are included in the apparatus. An apparatus of the sources is also provided.