"If words are used to convey intelligence, and if that intelligence is misleading, then the words are being used to deceive."

"When you are ignorant of the enemy's plans, you cannot prepare for them."

"Be subtle! be subtle! and use your spies for every kind of business."

"Rouse him, and learn the principle of his activity or inactivity. Force him to reveal himself, so as to find out his vulnerable spots."

"Know the ground, know the weather; your victory will then be complete."