Examines the evolution of microbial pathogenesis, capitalizing on explosion of knowledge of molecular mechanisms and microbial genome sequencing. Covers general concepts of microbial evolution including gene acquisition, gene loss, and concept of microbial species; presents information on broad areas of evolution of pathogenesis, including evolution of pathogenic microbes in soil, evolution of microbe-plant interactions, human specific pathogens, zoonotic infections, biofilm formation in the environment and pathogenesis, and co-evolution of pathogens and the immune system. Considers evolution of pathogenic systems found in a variety of microbes or specific subsets of pathogens.