The micropedological study of palaeosoils is an important tool to investigate the processes promoting soil formation and weathering in the past; it allows obtaining information about palaeoclimates and palaeoenvironments. Owing to some methodological bias, no clear consensus exists for the definition of palaeosoils; in view of these difficulties in proposing definitions and subdivision of palaeosoils, in this chapter we present an overview of micromorphological studies on various types of soil bodies recording pedogenic processes that occurred or started in the past. We include in the category of palaeosoils all soils developed in past environments and/or for which pedogenesis began in the past. Palaeosoil categories here considered include buried soils that are palaeosoils separated from the present-day surface, relict soils and polygenetic soils. The latter are palaeosoils that are not separated from the present-day surface; moreover, the significance of reworked palaeosoil fragments is also examined. Finally, we offer a micromorphological perspective on the study of rock coatings, which represent an initial stage of pedogenesis on aerially exposed rock surfaces. We discuss various examples of features that can be observed in thin section recording past pedogenic phases, if they are not in equilibrium with present-day pedoenvironmental conditions in terms of both climate and landscape position. In fact, literature review highlights that only if the effect of factors other than climate can be considered to be minimal, it will be possible to infer from micromorphological pedofeatures the true role of past climate in the formation of palaeosoils.
