Edward Thorp is seen to some as the Godfather of card counting. He was the first person to publish a book which mathematically proved that card counting (tracking high and low cards) could be used to beat the house edge in blackjack. This is detailed in his book Beat the Dealer .
A maths professor by profession, he put his knowledge to good use, eventually having to use disguises due to the reputation that he was developing in the casino world. This was the 1960s and beyond, so he was well ahead of his time.
He also used his mathematically abilities and techniques to beat other casino games such as baccarat, backgammon, and roulette. Some of the techniques used have now been stamped out by casinos, as they will of course go to any lengths to maintain their edge.