A fifth volume of infectious disease clinical pearls covering the common (influenza, staph) to the rare: rare bacteria in common locations, common bacteria in rare locations, and one-of-a-kind diagnostic dilemmas that in some cases are never fully resolved. Following Pasteur's dictum that "the microbe is nothing, the terrain is everything, " Crislip introduces the reader to a panoply of host factors in infection, from HIV infection to intravenous drug use to unusual variations in the immune system or the anatomy.