The only books in that vein I know are "The Art Of War" by Sun Tzu and Clausewitz' "Vom Kriege". I suspect german book shops don't tend to stock as many books on war as some other countries (I remember seeing the "military" section of a bookstore for the first time in London).

Anyway, I would be interested in more detailed stuff, like how to use tanks, planes and so on. Maybe analysis of historical battles would be good, too.

I guess it won't help with a startup, but for some reason I have wondered about this (maybe for strategy game development...).