**1. Introduction**

Soils are formed by the joint action of climatic factors, weather, relief, source material, and organisms. Source materials consist of rocks or other soils, under which the other factors work. Thus, the properties of a residual soil and the behavior it presents in the face of various requests will largely be determined by the rock or material from which it originated.

In tropical and intertropical regions, a diversity of climates and relief is observed, resulting in a very large variety of soils known as tropical.

Brazil, for its large size (more than 8 million square kilometers), presents geological, climatic, and relief diversity that has conditioned the formation of soils with various behaviors.

In general, the significant climatic factors for soil formation are mean precipitation and temperature, which condition the rates of chemical reactions, the rate of change of rocks as well as the mobility of elements along the profile. Formed from the leaching of bases and the concentration of oxides and iron and aluminum sesquioxides in this pedological evolution, we have the lateritic soils, which have properties differentiated from the soils formed in temperate climate.

Thus, considering the wide distribution of tropical climate in the world and its occurrence in much of the Brazilian territory, aspects on the genesis, importance, and properties of tropical soils in the country will be addressed in this chapter.
