The abundance of sulfate-reducing prokaryotes (SRP) is impressive and new isolates are being reported continuously. A few decades ago only 2 genera had been identified; today we know of at least 75. This book addresses the historical background of this field and its impact on future growth, and provides coverage of the diversity of SRP, their enzymatic processes, and environmental activities. It highlights the unique cellular and molecular features of these microorganisms, and discusses the production and consumption of gases and the biochemical interactions behind their metabolic capabilities. Examples are provided of detoxification reactions to alleviate pollution situations, the corrosion of ferrous compounds, and the effects of SRP on human and animal hosts.