There are techniques that can be very effective in the martial arts using cards. I haven't read this mans book, but I have studied the ways that cards may be useful to me if I happen to have them on me at the time and say the wrong thing to the wrong person (which I happen to do alot

).
Now I don't like to focus on the physical injury of one using cards, although it is very possible and I have done it before accidentally. I like to set my sights on what can help lead me into an attack, defensive movement, or what can help me flee. I prefer the latter to any physical conflict. You can try this one at home. Just make sure you don't actually have anyone in front of you. Especially their face
Stand with legs shoulder-width apart and and twist your upper body to the left away from the attacker(or to the right if you are left handed). Hold the deck in your non-dominant hand and bring your strong hand over top the deck. Twist your body back to the regular position and at the same time swipe a card out with your strong hand towards the attacker and let it fly. Do not try to force this to happen, like magic it takes practice. Bring back your strong hand to the deck but do not twist your body again. Repeat the movement of swiping the cards. After a few cards or when you feel the attacker is sufficiently confused, the rest is up to you. (I suggest running)
If you ever plan to use this, please make sure you have practiced hundreds of times. And for the love of all that is holy, if your attacker has a life threatening advantage, give him the money!
P.S. When my camera is up and working again I will upload some pics and maybe a movie of proper technique.
Elemental