Soils play an essential role in ecosystems, food security and health. In order to inform public policies concerning their proper functioning and preservation, a group of 19 experts from a variety of disciplines and public research organizations, coordinated by INRAE, analysed the scientific literature on soil quality and health. They gathered the main available resources and identified the key considerations for conducting an assessment based on the ecological functions performed by soils. Around 50 physical, chemical or biological indicators are thus associated with an interpretative framework that specifies the method of measurement or calculation and the reference values to which the result should be compared. The choice of indicators depends on the objectives of the assessment (development of an urban planning document, zoning of agricultural plots for land consolidation, etc.). The indicators need to be explained in order to select them, choose the interpretative framework and monitoring grid (spatial and temporal), and decide whether to aggregate some of them. This assessment promotes dialogue between users from different social and political backgrounds, encouraging them to reflect together on what soils are and what they are expected to be. This book is intended for non-experts with some knowledge on the subject: decision-makers, professional or associative actors, public services in charge of environmental and urban planning policies, etc. More broadly, it is aimed at anyone interested in the public debate on soil quality and health.