Anyone interested in our violent past, and how we got to our less-violent present, would be interested in The Better Angels of Our Nature by Steven Pinker. He g

Anyone interested in our violent past, and how we got to our less-violent present, would be interested in The Better Angels of Our Nature by Steven Pinker. He goes into great detail about how ridiculously violent the past was, and how much less violent we have become over time. Tl;dr: the concentration of permission to commit violence into the hands of the state has been a huge factor. As the numbers in the article here show, it is a rare state that can keep up with the level of violence that occurs naturally when individuals are having at it.