The present volume offers an edition, updated English translation of, introduction to, and seven multi-authored contributions on Galen’s small tract That the Best Doctor is also a Philosopher. The volume seeks to put Galen’s text into conversation with recent interrogations of medicine’s self-sufficiency – or disciplinary autonomy – in the Medical Humanities. As the title of the ancient work conveys and the essays in this volume unpack, Galen argues for a re-envisioning of medicine by making philosophy constitutive of his profession on the grounds that the latter’s methods of reasoning, explanations of the natural world, and ethical directives enable the doctor to understand and treat the body in disease. In so doing, Galen expands medical knowledge at the expanse of instrumentalizing the philosophical.