A wide-ranging study covering the significance of the Lower Palaeolithic lithic tool traditions usually referred to as Early, Middle and Late Acheulian and Clactonian. The work (concentrating on selected sites from the Upper and Middle Thames Valley) includes sections devoted to the interpretation of significant patterns of artefact manufacture and use and the question of the procurement and economic use of lithic raw material. Special emphasis is given to lithic styles and technology, recurrent morphological patterns within stone tool assemblages, and the effect of the varying distances between occupation sites and the lithic raw material sources.