This book explores the themes of health, medicine, and the origins of infectious disease in pre-industrial Italy. Using the papers of the Magistrato alla Sanita, the Florence Health Magistracy, covering the first 30 years of the 17th century, the author recreates the ecological and medical environment of the Florentine countryside. The book opens with an analysis of the Sanitation Office in Florence, the Uffici de Sanita, of its regional inspectors and their grasp of epidemiological principles. It reveals the transformation of the Office from a temporary administrative body into a permanent institution with preventative aims. And it documents, through their own verbatim accounts, the endeavours of intelligent and motivated doctors and medical inspectors to combat disease within a superstitious culture and an environment of dirt. The book shows how tantalizingly close was contemporary medical practice, focused on the physical elements, humours, and pungent exhalations, to the real sources of infection - dirt, rubbish, and sanitary effluents. Cipolla shows how, despite limitations in knowledge, the painful process of 17th century discovery provided the basis for modern medical insight.