This chapter reviews the development of agriculture in Britain and Ireland from the Neolithic period to the middle of the Bronze Age (approximately 4000 to 1500 bc in calendar years), and the associated questions of the identity of the people involved, the density of populations, and their effect on the landscape. This brief account is set in the context of the wider development of an agricultural way of life on the adjacent continental mainland, going as far back as 6000 bc in central Europe. I hope to raise questions as much as to answer them, and to concentrate wherever possible on new evidence and approaches. I should like to frame my discussion by setting out four hypotheses: 1. Overall, change was slow, but punctuated by spurts or accelerations (notably around 5500 bc, 4000 bc, and 1500 bc), whose nature is still poorly understood. This hypothesis stands in opposition to a general tendency to envisage a steadily intensifying evolution of subsistence methods, population levels, and landscapes. 2. There was much continuity of population both in continental Europe and in Britain and Ireland, but the role of colonization still needs seriously to be considered. This hypothesis seeks to re-examine both the assumption in continental research of major colonization with the onset of the Neolithic and the recent British consensus that the beginnings of the Neolithic were essentially to do with the acculturation of an indigenous population. 3. Although some landscapes had been cleared of substantial tracts of woodland by about 2500–2000 bc, population levels in most parts of Britain and Ireland remained relatively low at least until the middle of the Bronze Age, and the lifestyle can be characterized by continuing mobility and/or short-term sedentism. This hypothesis restates recent opposition to the notion that the introduction of agriculture entailed sedentary existence, rapidly growing population, and intensifying production right from the start. The coming of agriculture in a more familiar guise, although preceded in Britain and Ireland by herding and piecemeal cultivation from about 4000 bc, was not seen till as late as about 1500 bc onwards.