The key role of paleosols in the evolution of the biosphere-geosphere system raises the value of fundamental soil science for life and earth sciences. Paleosols studies are becoming more complex and are focusing of new interdisciplinary challenges. These are the biosphere evolution at the earliest stages, the coevolution of Life and Soil, Global Climate Change, etc. For planetary sciences, pedolithospheres (rocks, influenced by pedogenesis, weathering crusts and paleosols) are the only reliable evidence of prolonged continental environments in the Precambrian. For paleoclimatology, paleosols make it possible to reconstruct the dynamics of oxygen and carbon-dioxide content in the atmosphere, the alternation of arid and humid cycles in buried soils in cyclothems, loess-paleosol sequences, and other terrestrial archives. Paleosol studies play a key role in such traditional disciplines as geology, geomorphology, paleogeography, tephrochronology, limnology, and archaeology. Paleopedology is also important for sustainable land use: surface and exhumed paleosols form the relic basement of the day-time soilscape, determining many economically significant properties of agricultural land.