The biome approach to mapping vegetation change provides objective and replicable large-scale maps of past vegetation. These can be used to investigate biogeographic patterns and processes, aid in paleoclimate reconstruction, and help evaluate the performance of climate models. The process of biomization relates pollen abundance data (from fossil or modern pollen spectra) to plant functional types (PFTs) and PFTs to biomes, which are globally recognized vegetation types. Describing the data in terms of PFTs makes use of known plant–climate relationships; plant structure and function, not floristics, are the basis of the vegetation reconstructions. The approach avoids problems associated with trying to map disparate reconstructions of past vegetation related to differences in regional approach or paleoecological methodology. It also circumvents the problems inherent in the interpretation of past climate directly from fossil pollen data in cases where fossil assemblages have no modern counterparts. The approach was designed with the evaluation of climate model performance in mind and has been applied widely in this context. Typically, a vegetation model is driven by data from a paleoclimate simulation, and its output is compared with the mapped paleovegetation.