Galen (AD 129-c.200), researcher and scholar, surgeon and philosopher, logician, herbalist and personal physician to the emperor Marcus Aurelius, was an influential and multi-faceted medical author of antiquity. The work of Galen is interesting both for its innovations (especially in anatomy and in the physiology of the brain and the nervous and vascular systems) and for its remarkable synthesis of previous ideas, in particular the famous four-humour theory and the Platonic philosophy of the mind. He dominated medical theory and practice until the scientific revolution and beyond, through the medieval schools and through his influence on Muslim medicine. This volume functions as an essential introduction to his medical philosophy and includes translations of several major works. At the same time it presents an insight into medical practice and intellectual and everyday life in ancient Rome.