Book excerpt: The conclusion of this professor-historian (emeritus) is that our gun culture had its uses in establishing American civilization, as slavery did. But we came to recognize (after a bloody civil war) that slavery was a gigantic mistake, and now I think it’s time to realize that our gun culture was a similarly gigantic mistake, though of a different kind. And we need to do what we can to minimize its horrible impacts and move on to a more positive development of a humane civilization.