Technical Abstract: Soil biology represents a diverse group of organisms that reside during at least a part of their life cycle in the soil. Soil organisms can be primary producers of organic materials, but more commonly are heterotrophic consumers of preformed organic materials; essential in the cycling of nutrients and transfer of energy following the senescence of plant materials. Soil organisms also play major roles in soil structural development by forming biotic pores, transforming soil minerals and organic matter into stable aggregates, and catalyzing mineral weathering processes. Ecologically, soil organisms perform many key environmental functions, including (1) regulation of C cycling from plant detritus back to the atmosphere, (2) provision of inorganic N to plants through decomposition and biological N fixation, (3) transformation of nitrate via denitrification to mitigate water contamination, (4) biodegradation of natural and synthetic contaminants in soil, and (5) purification of water percolating through soil into groundwater. Soil biology is recognized as a key component for the development of land management systems by human society to help sustain and improve ecosystem functioning on local, regional, and global scales.