Residual soils are found in many parts of the world and are used extensively as construction materials for roads, embankments and dams, and to support the foundations of buildings, bridges and load-bearing pavements. The characteristics and engineering properties of residual soils can differ significantly from those of the more familiar transported soils. The fact that residual soils often occur in areas with tropical, sub-tropical and (extensively) in semi-arid climates, adds another dimension to their engineering performance, that of unsaturation. Although there are many books that deal with the mechanics of soils, these are based mainly on the characteristics and behaviour of saturated transported soils. The first edition of this book was the first book to be written specifically about the mechanics of residual soils. The book was prepared by a panel of authors drawn from the Technical Committee on Tropical and Residual Soils of the International Society for Soil Mechanics and Foundation Engineering. It was written as a practical professional guide for geotechnical engineers working with residual soils. The second edition has retained the valuable information contained in the first edition. The present editors/authors have extensively revised and augmented the contents to bring it completely up to date, adding significantly to the sections on unsaturated soil mechanics and to the range and number of instructive case histories. Sections on pedocretes, dispersive soils and karst have also been added.