This work originated from an interest in the history of ideas in medicine. I wanted to find out why our forefathers, almost to a man, believed that the proper way to treat most diseases was to remove blood from the patient, and as there was to my knowledge no published translation of Galen's three bloodletting works in any modern language, I made one from the Greek of Kühn's edition, and went on to consider where his ideas came from and how they developed in the course of a long and active life. The material was used in 1978 as a dissertation for the degree of M.A. in classics from the University of Natal. Subsequently the translations have been revised, and the discussion rewritten to make it more accessible to the general reader. An introductory chapter on Galen's system of pathology, based on subsequent reading, has been added, and the passages quoted in the text in Greek and in modern languages other than English have been translated. Although unfamiliar old terms are explained when first encountered, they have all been collected into a glossary for easy reference, together with such modern technical terms as may be unfamiliar to the non-specialist.

Kühn's text is corrupt in many places, and only one of the three works has had any critical attention. I have therefore examined a number of the manuscripts and early printed editions, which clear up some of the difficulties. I must make it clear, however, that the only aim has been to improve the translations, not to establish texts; I am not a philologist, even by inclination.