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.
Antoine-Henri JominiA 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.
Antoine-Henri JominiThe surprise of an army is now next to an impossibility. ... Prearranged surprises are rare and difficult because in order to plan one it becomes necessary to have an accurate knowledge of the enemy's camp.
Antoine-Henri JominiBut 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.
Antoine-Henri Jomini