This book covers the processes and nature of soil fertility degradation including erosion, physical, chemical and biological degradation, and management options for achieving soil fertility restoration including soil organic matter, productivity, environment and ecosystem services, and soil health and Sustainable Development Goals (SDGs). It is primarily restricted to the tropical and sub-tropical regions and soils of the orders, Oxisols, Alfisols, Ultisols, Inceptisols and Vertisols, used for dryland agricultural production, mostly in semi-arid and sub-humid climates. Also excluded from detailed consideration are metallic and synthetic organic pollutants and socio-economic aspects of fertility degradation and restoration of soils.