The FAQ for Steven's new book, The Better Angels of Our Nature: Why Violence Has Declined. Highly recommended, and well-informed about the similar work of Professor R.J. Rummel, whose several excellent books are free online at the University of Hawaii.
An excellent speech by Pinker on the topic of his previously mentioned book can be seen here, at TED.com.
The work of these brave intellectuals extends our comprehension of the enlightenment, and shows the way toward expanding circles of logic, compassion, and justice around each and every individual. I favor a renewed effort to reinstate proper juries in the USA as the best means at pursuing expanded enlightenment values.