In the words of one of his English contemporaries, Louis Pasteur was "the most perfect man who ever entered the kingdom of science." His contributions to the development of microbiology and medicine were profound, both practically (Pasteurization and vaccination) and theoretically (the germ model of disease). He spoke out forcefully on issues of the day, especially when they concerned public health, and his research included studies on rabies, anaerobic life, childbirth fever, silkworms, and beer. Rene Dubos's outstanding biography examines Pasteur's manifold genius in the context of the...