The loss of biological diversity has become an increased concern over recent years and is now enshrined in international conventions. Most biodiversity in fact occurs in the soil. Soil organisms (especially bacteria, fungi and soil invertebrates) play a major role in the formation of soil structure and are primary agents of decomposition and are drivers of nutrient cycling, and hence agricultural production.This book reviews soil biodiversity in one of the key biodiversity hotspots of the world, i.e. the Amazon and nearby regions of Brazil. It covers both the tropical savannah and rain forests . The work reported is based on a project "Conservation and Sustainable Management of Below-Ground Biodiversity", executed by TSBF-CIAT with co-financing from the Global Environment Facility (GEF) and implementation support from the United Nations Environment Programme (UNEP). The book represents a major contribution to the literature and will interest those in biodiversity conservation, soil science and ecology and biodiversity conservation.