There's quite a few from that period of time that are all around the same thing, a few with conflicting views about how to conduct a war. This one I have is great because it gives an historical introduction about the dynastys, people, Sun-Tzu, warring states period and basically everything which brought about the Art of War.
There's seven military classics from that period but I don't know if they've all been translated into English. And plus, I'm getting a book on Nomonhon (Khalkin-Gol) soon and that's going to take me ages to read; it's 1,423 pages!