Of all those in the army close to the commander, none is more intimate than the secret agent.

The end and aim of spying in all its five varieties is knowledge of the enemy; and this knowledge can only be derived, in the first instance, from the converted spy. Hence it is essential that the converted spy be treated with the utmost liberality.

If it is to your advantage, make a forward move; if not, stay where you are.

Sweat more during peace: bleed less during war

If I am able to determine the enemy's dispositions while at the same time I conceal my own, then I can concentrate and he must divide.

In your deliberations, when seeking to determine the military conditions, let them be made the basis of a comparison, in this wise: which of the two generals has the most ability? on which side is Discipline most rigorously enforced? which army is stronger? on which side are the officers and men more highly trained? in which army is there the greater constancy both in reward and punishment?

Invincibility depends on one's self; the enemy's vulnerability on him.