Edward Golub shows in this text that major advances in medicine are caused by changes in the way scientists describe disease. Bleeding, sweating and other treatments we consider barbaric were standard traetments for centuries because they conformed to a conception of disease shared by patients and doctors. Scientific breakthroughs in the understanding of disease in the 19th-century transformed treatment and the goals of medicine. Golub argues that the ongoing revolution in molecular genetics has opened the door to the biology of complexity, again transforming the view of disease.