This book provides an account of how the early ape-men of the African Savanna developed into fully human beings. Leakey has always been interested in far more than the mere physical features presented by the fossils, and here he is particularly concerned with non-tangible human attributes. Thus there are chapters on economic co-operation, art, language, and consciousness itself. This is a more technical book than the earlier "Origins" and "Origins Reconsidered", giving the intelligent reader access to the complexities of the subject, but nevertheless very clearly presented.