A state attacked by another which renews an old claim rarely yields it without a war: it prefers to defend its territory, as is always more honorable. But it may be advantageous to take the offensive, instead of awaiting the attack on the frontiers.
One of the surest ways of forming good combinations in war would be to order movements only after obtaining perfect information of the enemy's proceedings. In fact, how can any man say what he should do himself; if he is ignorant what his adversary is about?
But it is almost impossible to communicate with them [one's spies in the enemy camp] and receive the information they possess ... Even when the general receives from his spies information of movements, he still knows nothing of those which may since have taken place, nor of what the enemy is going finally to attempt.
This [a surprise attack] is an operation by no means to be despised in war, although it is rare, and less brilliant than a great strategic combination which renders victory certain even before the battle is fought.