This is the fifth volume in the important Koobi Fora series on human origins, covering archaeological finds from excavations at East Turkana in northern Kenya. Volume 5 concentrates on the evidence from the period between 1.9 and 0.7 million years ago and reconstructs the behaviour of early human ancestors. The book answers such questions as: How were the stone tools made and utilized? How large were the groups of hominids, and how mobile? Do animal bones really give us a true impression of what food they ate? The stone artefacts, bones, and features of the ancient landscape recorded in this book provide a solid basis for further work on human evolution.