Sun Tzu was probably the greatest tactician the world of military has ever seen. the Art of War is an Exellent guide to running not only military, but life as well. But I rank him low because he does not have many significant Military achievements.

Sun Tzu's The Art of War is probably the single best tactical military piece from BC times. Not only that, it's a useful book to read for the purposes of living a high stakes life, such as working at the Stock Market. Effective, even if sometimes brutal.

All the officers read The Art of War.

There is not much easily reachable information on Sun Tzu, however it seems that he did know a lot about military tactics. Although he did not have a lot of powerful enemies to use these tactics against, thus, limiting his military achievements.