This book summarizes current advances in our understanding of how infectious disease represents an ecological interaction between a pathogenic microorganism and the host species in which that microbe causes illness. The contributing authors explain that pathogenic microorganisms often also have broader ecological connections, which can include a natural environmental presence; possible transmission by vehicles such as air, water, and food; and interactions with other host species, including vectors for which the microbe either may or may not be pathogenic. This field of science has been dubbed disease ecology, and the chapters that examine it have been grouped into three sections. The first section introduces both the