Margaret MacMillan's “War; How Conflict Shaped Us” is an extraordinarily information dense 270 pages.
That wars are good for us is a more likely conclusion for this book than the hackneyed 'war is hell'. While the Canadian historian doesn't say it is more one than the other, she gives space to both, but seems to favour that it has ultimately been more beneficial, at least the way it has played out so far with the technology available.