The second edition of this widely cited textbook continues to provide a concise but comprehensive introduction to cave and subterranean biology, describing this fascinating habitat and its biodiversity. It covers a range of biological processes including ecosystem function, evolution and adaptation, community ecology, biogeography, and conservation. The authors draw on a global range of examples and case studies from both caves and non-cave subterranean habitats. One of the barriers to the study of subterranean biology has been the extraordinarily large number of specialized terms used by researchers; the authors explain these terms clearly and minimize the number that they use. This new edition retains the same 10 chapter structure of the original, but the content has been thoroughly revised and updated throughout to reflect the huge increase in publications concerning subterranean biology over the last decade.