P. N. Singer is an Honorary Research Fellow at Birkbeck, University of London. His publications include several volumes in the Cambridge Galen Translations series; Time for the Ancients: Measurement, Theory, Experience; Mental Illness in Ancient Medicine: from Celsus to Paul of Aegina (co-edited with Chiara Thumiger) and The Oxford Handbook of Galen (co-edited with Ralph Rosen)