This profusely illustrated book gives an exhaustive account of the principal types of soils of our planet. The progressive descent of weathering fronts model, recognized and used by eminent international scientists is the guiding principle of choice to link the observations and to give the reader a synthetic and coherent view of the differentiation of soils. In each case, the introductory reminders summarize the physicochemical and mineralogical principles necessary for understanding the text. The nomenclatures rely systematically and simultaneously on the two most commonly used classifications: Soil Taxonomy and World Reference Base. This reference manual is aimed at students of the undergraduate and graduate courses, but is also intended for workers and scientists in this subject area (geologists, pedologists, agronomists, land-use planners, foresters, etc.) as well as for all those concerned with or interested in protection of the environment.