Ive read up some of Karl Von Clausewitz, The author of "On War", "The Art of War" by sun tzu & "Five Rings" by Miyamoto Musashi plus some of Machiavelli's "The prince" and wondered how much of an influence these writings have on your story line and game design?
If not then I would like to suggest "the Art of War" as my favourite which I read up on playing Xcom Apocalypse. I went from quitting the game
to finishing in 3 to 6 months
I recommend chapter 4 To understand the risk to reward ratio that needs to be modelled better in the game