“Generally in the case of armies you wish to strike, cities you wish to attack, and people you wish to assassinate, you must know the names of the garrison commander, the staff officers, the ushers, gate keepers, and the bodyguards. You must instruct your agents to inquire into these matters in minute detail. If you wish to conduct offensive war you must know the men employed by the enemy. Are they wise or stupid, clever or clumsy? Having assessed their qualities, you prepare appropriate measures.”
Book:The Art of War
