Alfisol, the dominant soil order in semi arid tropics of the world, are the most degraded owing to several natural and anthropogenic causes. Long-term studies were undertaken to improve and assess the quality of these soils. This book is the outcome of various experiences gained during the study and comprises of concepts of soil quality, indicators to assess soil quality, methodologies for estimation of various soil quality indicators and soil quality assessment, past research experiences on the impact of soil and nutrient management practices on soil quality and soil quality indices, case studies on soil quality assessment under long term management practices, future thrusts and research needs. As the modern concepts of viewing soil quality are different from those which were perceived three decades earlier, authors trust that this publication would be of immense use to all categories of stakeholders associated with agriculture viz., researchers, students, NGOs and officials of State Agricultural Departments in general and land care and soil managers in particular across the arid and semi-arid Alfisol and associated soil regions of the world.