The Surprise Attack is one of the oldest and most used theories, The basic idea is for a force of fast moving and lightly armored units to quickly attack the enemy in his weakest spot at the most unlikely time. The result often being a overwhelmed and confused enemy that makes rash and hasty command mistakes. The blitz wave is a good example of this. A good real life example of this is the Germanic attack on Roman forces at the Battle of the Teutoberg Forest,in 9AD.
The only way to make use of this strategy is to have a very well disciplined and extremely dedicated force. The famous Nazi general, Erwin Rommel, used this strategy extensively in North Africa against the British.
To counter the threat of a surprise attack is to be always on top red alert, and to leave no openings. And never underestimate your enemy.