The Bible is the bestselling book of all time. It has been venerated&emdash;or excoriated--as God's word, but so far no one has read the Bible for what it is: humanity's diary, chronicling our ancestors' valiant attempts to cope with the trials and tribulations of life on Earth.

In The Good Book of Human Nature, evolutionary anthropologist Carel van Schaik and historian Kai Michel advance a new view of Homo sapiens' cultural evolution. The Bible, they argue, was written to make sense of the single greatest change in history: the transition from egalitarian hunter-gatherer to...