"What enables the wise ruler and good general to strike, conquer, and achieve things beyond the reach of ordinary men is foreknowledge." - Sun Tzu, "The Art of War."

The judicious use of scouts and spies constituted its own chapter in Sun Tzu's manual. It was an indispensable part of ancient warfare in any location and time frame. Knowledge of terrain, of the persons leading the enemy army, and the conditions of the armies themselves were key elements which could spell success or ruin for a campaign, and the great general stressed that no amount of care, money, or sagacity was too much to spend in such endeavors.
