Publisher Summary This chapter outlines the study of Quaternary insect fossils, which is most fully developed for sites in Western Europe, especially Great Britain. These studies have made an impact on regional Quaternary studies, especially in the study of climate change. Most European research has focused fossil assemblages dating to the last glacial—interglacial cycle, but numerous others of Middle Pleistocene age are investigated. In Britain, it is very difficult to assign a reliable age to most fossil assemblages older than the last interglaciation. The fossil insect faunas that date from the last interglaciation (MIS 5) through the Holocene are focused in the chapter. The sequence of climatic changes from Coope's landmark is summarized. While the timing of the Early to Middle Devensian (MIS 4 and 3) events is substantially revised since 1977, the interpretations of the sequence and intensity of changes is essentially the same. A fossil insect assemblage from the type locality at Bobbitshole, Ipswich is also described. The fauna is deposited in a shallow, eutrophic pond or lake, with abundant marsh vegetation. The composition of the assemblage closely matches that from Trafalgar Square.