A really quite seriously beautiful look into this huge and well travelled subject.
What can Shermer add to the huge pile of debate and polemic already out there on this topic? Rational inquiry based upon evidence. This makes his contribution very different to most. Evolutionary theory, morality and determinism are examined thoughtfully.
Next he examines the religious claims on this topic and develops "provisional ethics" as a rational alternative to blind faith and obedience.
If only more folks would prefer thinking about morality rather than judging others based on the morality they think has been dictated to them, then I think the world would be a far better place.
So go and read this, and then think about it.
Four out of five stars.