This book is written in 10 chapters. It begins with a chapter on formation, classification and distribution of two important soil orders in the world, the Ultisols and Oxisols. Farming communities in the tropics make their living by using the soils productively for their agricultural enterprises. The main part of the book deals with the chemical properties of the soil groups, including charging phenomena that make the soils what they are. Other chapters discuss the management of Ultisols and Oxisols for sustainable crop production.