I know that conflict is the less civilized side of civilization, and that HN generally is opposed to it (as sane people are), but a discussion of societal development would be lacking without an honest consideration of where the civilized components break down. I would suggest Musashi (http://en.wikipedia.org/wiki/The_Book_of_Five_Rings), Clausewitz, Influence of Seapower Upon History (Mahan), and of course Sun Tzu. While some are more specific than others (Musashi is actually about swordsmanship specifically, but conflict generally) they all have insightful things to teach. For a broader discussion look at Bobbitt's Shield of Achilles. He still has a significant portion on conflict, however it is also a discussion on the interplay of technology, legal development, and conflict.
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