Soil has generally been regarded as something of a 'black box' by ecologists. The importance of soil is obvious: it provides physical support for plants, and both the living and non-living components contribute to a variety of important environmental functions. Soil is a species-rich habitat, but many questions about the ecological significance of the soil's biological diversity, and in particular how it affects ecosystem function, have never been asked. The linkages between above-ground ecology, which is rich in ecological theory, and below-ground ecology, where investigation has been restricted by methodological difficulties, have not been made. Technical developments, including isotopic and molecular methods as well as experimental and modelling approaches, have led to a renaissance in soil biodiversity research. The key areas are reflected in this exciting volume which brings together many leading contributors to explore the role and importance of soil biota.

RICHARD D. BARDGETT is Professor of Ecology at Lancaster University and has published widely on plant-soil interactions, nutrient cycling, and soil ecology. He is especially interested in studying linkages between plant and soil biological communities, and examining how these links are affected by herbivores.

MICHAEL B. USHER is retired. For more than 40 years he has had a research interest in the soil biota, especially the Collembola (springtails), Isoptera (termites) and Mesostigmata (mostly predatory mites). He also has a strong interest in nature conservation, and is currently working on a number of aspects of the conservation of biodiversity.

DAVID W. HOPKINS is Professor of Environmental Science at the University of Stirling and has research expertise in soils science and ecology, especially the biology and biochemistry of nutrient cycling. His research involves ecological, environmental and archaeological projects.