This book starts with a paradox and ends with a riddle. The paradox notes that the mammal specie with the most capable adults is the mammal specie with the most hekpless of babies. Is there a connection? The author contends that there is. He attempts to show how the evolution of the helpless baby has led to reciprocal genetic and behavioural adaptions of the nursing females. In addition, the increasing length of the baby's helplessness resulted in the development of the hominid multi-age brood. The author shows how the Long and Short Birth Interval multi-age broods led to social sharing,...