This book presents a translation of and detailed commentary on Galen's De alimentorum facultatibus - his major work on the dynamics and kinetics of various foods. It is thus primarily a physiological treatise rather than a materia medica or a work on pathology. Galen commences with a short section on the epistemology of medicine, with a discussion on the attainment, through apodeixis or demonstration, of scientific truth - a discussion which reveals the Aristotelian roots of his thinking. The text then covers a wide range of foods, both common and exotic. Some, such as cereals, legumes, dairy products and the grape, receive an emphasis that reflects their importance at the time; others are treated more cursorily. Dr Powell, an expert in gastroenterology, discusses Galen's terminology and the background to his views on physiology and pathology in his introduction, while John Wilkins' foreword concentrates on the structural and cultural aspects of the work.