While some of the earliest regular aerial reconnaissance for archaeology was carried out in the south and east of Britain, work in west has been of more recent date. The emphasis has chiefly been upon the well preserved archaeology of the western uplands such as Dartmoor and Bodmin Moor, where aerial photography has played a very important role in the mapping of the upstanding monuments. The archaeological understanding of the South West England and Wales has been dominated by the archaeology of these uplands, which were long believed to have been preferentially occupied in the prehistoric period. Since the 1950s, however, reconnaissance by Professeur St Joseph and David Wilson from Cambridge, has indicated that these areas can also be productive of cropmarks, and the last ten years have seen the development of regional flying programmes examining these areas through more intensive survey. Climate,soil and cropping conditions in the west are all substantially less favourable to cropmark production than in the east, and locally based flying represents the most efficient and effective way to exploit the narrower windows of opportunity. Results over the last fifteen years have transformed our perception of the later prehistoric and Romano-British settlement of the lowlands of South West England and Wales, the nature of the Roman Conquest and the changing relationship between highland and lowland areas.