This third volume, One Big Happy Family, circles back to the reality that all of us are nudged in this direction or that, when it comes to our political and social biases, by our genes and by the differences in our individual brains - and that this variety is a gift of nature, equipping the human tribe for optimum survival. The idea is to emphasize that our deep political divisions are ultimately foolish and even dangerous, and that we do better when we realize that we all see the world differently by nature's design, and that this truth should be celebrated, not denigrated.