P. N. Singer is a Research Fellow at the Einstein Center Chronoi, Berlin, and an Honorary Research Fellow at Birkbeck, University of London. His publications include several volumes in the Cambridge Galen Translations series, Mental Illness in Ancient Medicine: From Celsus to Paul of Aegina (co-edited with Chiara Thumiger), and Time for the Ancients: Measurement, Theory, Experience.
Ralph M. Rosen is Vartan Gregorian Professor of the Humanities and Classical Studies at the University of Pennsylvania. His publications include Ancient Concepts of the Hippocratic (co-edited with Lesley Dean-Jones), Making Mockery: The Poetics of Ancient Satire, several volumes in the Penn-Leiden series on Ancient Values (co-edited with Ineke Sluiter) and numerous other writings on Greek literature, ancient medicine, and intellectual history.