Here's some material that I've been doing research from for my current game. Being a programmer, you maybe suprised that I read something other then technical books. but you can't make fun games if all you read is super advanced 3d quaternion math, so I indulge myself in research that can help me develop of fun foundation for a game.
Books I've just picked up and are using for my current research:
1.) Connection Games.
2.) Hex Strategy.
Books I've been reading lately include:
1.) Numbers, Predictions and War.
3.) Supply War.
4.) Understanding War.
1.) On Clausewitz.
2.) Masters of War: Classical Strategic Thought.
I'm a student of military thought and a lot of my games research involves digesting material from books such as : A History of Military Thought (Gat), Anything with Clausewitz in the title (On War, Masters of War, Understanding War, Clausewitz and modern strategy, On Clauswitz is exceptionally good and Clausewitz and the State.)