Soil organisms are largely out of sight and mind. Yet, soil is home to a staggering 59% of all species on Earth; species that act as major drivers of the structure and functioning of our vital terrestrial ecosystems. Our understanding of this hidden diversity still lags on what is known about biodiversity above-ground, and it is largely ignored by international biodiversity conventions. But interest in soil biodiversity is booming, reflecting a growing awareness of the importance of soil life for the health of natural and managed ecosystems, and of the many services soil biodiversity provides for a healthy planet. The Ecology of Soil explores what is known about the diversity of life in soil, how it is distributed in space and time, and how interactions between soil organisms, plants, and their consumers shape terrestrial ecosystems. It also provides an assessment of how soil biodiversity and its many functional roles are modified by global change, especially land use and climate change, and how soil ecology knowledge can be harnessed to address sustainability challenges of sustainable agriculture, ecosystem restoration, and climate change mitigation and adaptation. By drawing on a rich diversity of soil ecology knowledge from ecosystems of the world, and from the foundational to the new, this fascinating book provides the most comprehensive and up-to-date assessment of the ecology of soil and its importance for a healthy planet. Detailed and accessible, The Ecology of Soil is suitable for both undergraduate and graduate students, and will inspire any reader to delve deeper into the ecology of soil.