This chapter introduces some of the key concepts presented within this publication that link the soil nitrogen (N) cycle with the health of managed soils. We explore the evolution of definitions and of understanding of the importance of soil health, its importance in supporting ecosystem services, and indicators of soil health. This is within the context of the soil N cycle, for which we provide an overview of key processes and environmental impacts, particularly contributions to climate change. Soil N cycling and soil health are intricately linked through influences on soil biological, physical, and chemical properties, within which we emphasize the important roles of soil organic matter and the soil microbial community. These relationships have implications for appropriate soil management and the need to ensure practices strengthen soil resilience to a changing climate.