Galen. At the top of the pyramid of medical care providers that characterized the medical marketplace was a small group of elite physicians who were extensively trained in the liberal arts and academic medicine at one of Europe's universities. Medicine for this group was defined by an intimate knowledge of classical Greek theories about health and disease that was conveyed principally in the works of antiquity's greatest medical writer, Galen (second century C.E). Galen's medicine came to the Latin West first by way of Arabic versions of his writings or commentaries on them, which were rendered into Latin in the eleventh to the thirteenth centuries, and later in translations made directly from Greek manuscripts imported from Byzantium or discovered in remote monastic libraries. Recovery of these texts was uneven, with the therapeutic and general-theory treatises reaching Western readers before...