Some of the most terrifying moments of my life have been in the midst of conflict: with American marines in Fallujah in 2004 and with armed bands in Sierra Leone in 1993. I stood next to mounds of dead Iranian soldiers, teenagers actually, during the Iran-Iraq War in 1984. The horror of war is a reality I have experienced firsthand. And yet an analyst must never give in to his or her emotions. He or she must view history with a heart of ice to find patterns that others miss. This is what Stanford classics professor Ian Morris does in his new book, War! What Is It Good For? Conflict and the Progress of Civilization from Primates to Robots. Morris, both an archaeologist and a historian, surveys thousands of years of history and comes away with the seemingly startling thesis that human progress has been helped, rather than hindered, by war.

As he writes, "by fighting wars, people have created larger, more organized societies that have reduced the risk that their members will die violently."

Indeed, in the Stone Age, you had as much as a 20 percent chance of dying violently at the hands of another human being. But in the 20th century - even with the trenches, even with Hitler, with Hiroshima, with terrorism and with a panoply of Third World wars - you had only a 1 or 2 percent chance of dying violently. Yes, as many as 200 million people may have died in wars throughout the 1900s, but roughly 10 billion lives were lived during that period. One may argue that this has merely been a matter of food production outpacing the production of assault rifles, so that violence has not so much been suppressed as overwhelmed by science. But Morris sees another factor: the rise of Hobbesian Leviathans that could only come about by war itself.

A Leviathan is the horrifying monster that Job beheld in the Bible, the "king over all the children of pride." The 17th century English philosopher Thomas Hobbes used the concept as a metaphor for a strong central government that, by monopolizing the use of force, would make men no longer fear each other but only the authorities above them. Such was the way toward peaceful progress. Morris shows that, ironically, throughout history Leviathan has generally been created not by reasoned discussion but by war. He laments that this is so but demonstrates that humanity has thus far found no other way.

Morris recounts the sheer dreadfulness of Rome's conquests over the northern tribes of Europe. "Rome had made a wasteland and called it peace," went the famous adage. But that wasteland, he goes on, became the most productive and the most developed part of Greater Europe and the Mediterranean basin, even as life under Roman rule was safer and more predictable for the average person compared to any of the so-called barbarian precincts adjacent to Rome. Leviathan quelled violence, even as it demanded it. The political philosopher Francis Fukuyama in his 2011 book, The Origins of Political Order, posed the question, how do we get to Denmark - Denmark being a metaphor for a humane and efficient polity? Morris essentially answers that we get to Denmark by starting with Rome.

A theme that runs through Morris' book is that while some idealists worship primitive societies and the noble savages who populate them, primitive societies rather than idyllic retreats have more often been filled with the terrifying human monsters associated with William Golding's 1954 novel, Lord of the Flies. Thus, the idea is to incorporate primitive societies within Leviathan, and that has usually happened through military conquest.