Microorganisms are key components in the functioning of ecosystems and the importance of their role is being increasingly recognized. In this volume, more than thirty contributors, invited from around the world, cover a wide range of topics: the extent of microbial diversity, the impact of microorganisms on global ecology and nutrient cycling, microorganisms and ecosystem maintenance, extremophiles, inventorying and monitoring microorganisms and the microbiology resource base. The book is based on papers presented at an IUBS/IUMS/SCOPE/UNEP-sponsored workshop on Microorganisms and the Maintenance of Biodiversity held in the UK in August 1993. It provides an up-to-date review of concepts and concerns in this increasingly important area of biodiversity studies, and will interest a wide range of ecologists and microbiologists.