Basic definitions used in paleopedology include paleosol as soil formed on a landscape during the geologic past that could be either buried, surface (relic soil), or exhumed. Buried paleosols are subjected to diagenesis, which is a set of chemical, physical, and biological processes related to the transformation of soil after burial beneath younger deposits. Paleosols could be presented by monogenetic, polygenetic, accretionary, or compound profiles and pedocomplexes. They could be truncated or redeposited (Pedolith) in colluvial sequences. In the geologic history of the Earth, paleosols are included in the biogeosphere cycles, being completely transferred in its entire mass over significant distances into other earth layers, ceasing its existence as soil but bringing into these earth layers that make up the pedolithosphere, the chemical energy given to it by the activity of living matter. The study of paleosols includes their identification, dating, and paleolandscape interpretation. The major archives of paleosols include loess–paleosol sequences, volcanic deposits, fluvial series and lake sediments, sand dunes, colluvial sediments, weathering crusts, coalbeds, and geoarchaeological monuments. Paleosols allow sediments of different ages to be distinguished and play a key role in sequence stratigraphy (pedostratigraphy). The problem of classifying paleosols within existing systems is related to their inherent properties: many features important for classification are missing or changed by diagenesis.