Two core philosophies underlie the second edition of ‘Parasitism’, co-authored by myself and my brother Cam Goater, and graduate school mentor, Jerry Esch. The first is that the complex interactions that occur between parasites and their hosts – from the molecular cross-talk that occurs at the host-parasite interface, to the effects of parasites on host communities – are fundamentally ecological. The second is that a real appreciation for the phenomenon of parasitism requires knowledge of how natural selection has shaped parasite life cycles, life histories, and morphologies to solve particular problems associated with the parasitic lifestyle. Thus, for senior undergraduates that are being introduced to the phenomenon of parasitism in animals, the authors see a need for a single text with dual focus on the biodiversity and ecology/evolution of parasites. This dual, interdisciplinary approach, under one cover, is the hallmark of the text. The 17 chapters, 8 of which are new since the first edition, have been thoroughly revised to meet the needs of a new generation of parasitology students, whether their interests lie in ecology, conservation biology, evolution, immunology, or in the medical, wildlife, or veterinary sciences.