This collection of translations of some of Koch's important essays represents an important first. It includes three of his essays on anthrax, three on tuberculosis, two on cholera, one on wound infections, and a relective essay entitled On Bacteriological Research. These papers clearly reflect the coherence and inter-connectedness of Koch's thought. They include the initial presentation of his ideas and also provide examples of his tenacious and devasting responses to his critics. While they only represent some of the many areas of Koch's interests, they serve as excellent samples of his finest contributions. The volume also includes a long introduction which establishes the historical context of Koch's work and of the particular essays translated here.