Complexity of interpretation of the archaeological evidence about early human migrations here concerns both the exclusively African origin of the earliest ancestors of the species Homo, and the African or polycentric genesis of Anatomically Modern Humans (AMH). Through the medium of tool production remains - blade technologies in particular - Kozlowski traces the chronology of early extra-African migrations to re-examine their causes, including environmental change. Technological innovations prove to be a means by which the population movements of North Africa and Southern Europe can be tracked: from the archaic Homo sapiens to AMH (600,000 to 200/150,000 years BP); and the subsequent spread of AMH (50,000 to 30,000 BP).