This chapter reviews the evidence for the late fifth and early fourth millennia cal bc in the Thames Valley. Throughout the period under study, there are strong strands of continuity. The utilization of tree-throw holes, the small-scale digging of pits, the creation and abandonment of occupation spreads, and the accumulation of occupation material into middens are common to both periods. However, in the fourth millennium cal bc, communities began to alter their landscape through increasingly substantial building projects: first houses and then monuments. There was more visible treatment of the dead and deposition of human remains. Clearings became more extensive, perhaps largely for pasture, and small cultivation plots were created. Cereals, domesticated animals, new flint tools, and Carinated Bowls are found on all sites from the beginning of the fourth millennium cal bc. It is tempting to try to rationalize this evidence into explanations of either indigenous populations adopting a new way of life, using the evidence of continuity (which is strong); or incomers, pioneer farmers bringing their own material culture and different social practices, as witnessed by the new elements in the archaeological record. But perhaps we should not be thinking in terms of either/or, but rather both.