Laboratory medicine developed in the nineteenth century, principally in Germany, France, Britain, and the United States of America. While a number of scholars have studied various aspects of laboratory medicine in the nineteenth century, no attempts have hitherto been made to synthesise such work and to present a view of the whole subject. This book brings together leading researchers on the history of laboratory medicine in Europe and America. Each brings their special expertise to bear on the general subject of the nature and genesis of laboratory medicine. Together, they provide a much needed account of how medicine in Western industrial societies acquired its distinctive power and authority through association with the laboratory. These historical studies are followed by a short concluding section of 'Reflexions' by scholars from the fields of laboratory studies, philosophy of science, and gender studies.