Bacterial Biogeochemistry: The Ecophysiology of Mineral Cycling, Fourth Edition , discusses the influence of bacterial activity on the chemical environment of the biosphere. Following the success of previous editions, this fourth edition focuses on bacterial metabolism and its relevance to the environment, including the decomposition of soil, food chains, nitrogen fixation, assimilation and reduction of carbon nitrogen and sulfur, and microbial symbiosis. All chapters have been revised and brought up to date in light of the many advances and discoveries that have taken place during the last decade, and the scope of the new edition has broadened to provide a review of the processes and phenomena that are relevant for global change feedback loops and advances in bacterial biogeochemical cycles.