This chapter provides an overview of soil biology, health and ecosystem services. The authors present an update on previous work by integrating the chemical and physical components of soil health with that of the biologically mediated processes and further define how environmental conditions may contribute. To achieve this, four soil function cognitive models have been developed: (1) Carbon and Climate Regulation, 2) Nutrient Cycling, 3) Water Regulation and Filtration and 4) Habitat Provision for Biodiversity. The four cognitive models offer a structured way to integrate biodiversity into soil health assessments, alongside chemical, physical and environmental parameters, ensuring that biological indicators are given appropriate weight in evaluation frameworks.