I don't want to spoil Dave's answer, so if you're reading this dave: post before you continue reading:
Nien! Just my opinion, a lot of people contest this but I consider the book universal!
-Victorious generals win, then go to war
-He who knows himself and his enemy need not fear the result of a thousand battles
-Defeating your enemy without fighting is the supreme art of war
-Strategy without tactics is the slowest route to victory. Tactics without strategy is the noise before defeat.
-All warfare is based on deception.
These are all brilliant advice in politics, economy, and in life! Conflict is unfortunately a universal human experience.
Remember that war is won by economy and politics, not by strength of arm! Remember GoT? Rob Stark won every battle, and lost the war!
...obviously I'm quite a fan of Sun Tzu, having commited these quotes to memory!