Book excerpt: Quantifying and Modeling Soil Structure Dynamics emphasizes a systems approach to how soil structure changes in response to inputs and to the environment. Soil structure is a dynamic, complex system affected by tillage, wheel traffic, roots, soil life, shrink–swell, and freeze–thaw. In turn, soil structure affects root growth and function, soil fauna, solute transport, water infiltration, gas exchange, thermal and electrical conductivities, traffic bearing capacity, and more. Ignoring soil structure or viewing it as “static” can lead to poor predictions and management. Readers will especially appreciate the description of soil structure influence on endpoints, such as environmental contamination and efficient water use, and how models should be adjusted to include dynamic soil structure components for accurate outputs.