In the 4th century B.C., philosophers began to write not only philosophical texts, but also biographical ones. As biographers, they often presented members of their own schools as the epitome of their ideals, or tried to prove that the followers of others lived in ways inconsistent with their own doctrines, which the writers thereby hoped to show were ultimately unrealizable. Other biographies contained chapters engaging in doxographical or more properly philosophical discussions. Even when the philosopher-biographers’ attention turned to the lives of politicians and poets, they would find occasions to introduce their philosophical concerns. This whole genre of Greek biography, then, is an rich source of commentary on the philosophical doctrines current in Antiquity. The papers collected in this volume explore the many ways in which philosophy was incorporated into such texts, as well as how the genre was used as a means of philosophical instruction, discussion and polemics. They analyze texts from the 4th century B.C. to the 6th century A.D., some belonging to the best-known examples of the genre, and others being virtually unknown to most students of Antiquity. The volume contains studies of, among others, Dicaearchus, Timaeus, Philodemus, Plutarch, Lucian, Iamblichus, Philostratus, Eunapius and the anonymous Prolegomena to Plato’s Philosophy.