Sun Zi: The Art of War & Sun Bin: The Art of War
Art of War: Niccolo Machiavelli
by Niccolo Machiavelli
On war (Vom Kriege) Clausewitz
Maurice's Strategikon: Handbook of Byzantine Military Strategy
I am not sure if the books linked above are the best version (I own several of them in German, not English) but I guess the titles itself derserve a place here. Further I could not find suitable links for other works like Bellum Gallicum or 36 stratagems.