Seen through the eye of a satellite orbiting our planet, southern Africa has the light green tint of open savanna over most of its central and eastern extent. On the western side of the continent, as the gaze shifts towards the Atlantic coast, lies a pale landscape of dunes and gravel plains: the Namib Desert and the adjacent semi-arid interior. Here, modern humans and their ancestors adapted with increasing ingenuity to ecological opportunities and constraints that shifted back and forth over millennia in response to fluctuations in global climate.