the sustainability of both natural and managed ecosystems is strongly influenced by soil biological processes. a major question in soil biology and ecosystem ecology is the extent to which these processes are affected by the function and structure of the soils biotic community. the significance and regulation of soil biodiversity presents the discussions of a group of soil biologists and ecosystem ecologists in which they synthesize available information, present innovative methodologies, and develop cross-taxa and cross-habitat collaborations to advance our understanding of soil biodiversity. the volume addresses the extent and regulation of soil biodiversity and describes initial approaches to the linking of soil biodiversity and ecosystem function. audience: researchers and students in a wide range of environmental scientific disciplines.