This is a great book that everybody should (try to) read. OK, it's 700 pages of tiny print, so beyond my capability, but I did read all but chapters 8 and 9. That means I got all of the author's lively description of how violence has declined dramatically, but I missed some of the description of brain structures that explain why this might be true. But even without the "why" of the sub-title I loved this book, mostly for its debunking of conventional wisdom and its humor. Within the constraints of those 700 pages of tiny print, it's actually quite readable. My big disappointment is that it was published in 2011. I would have loved to have heard his take on Trump.