Authored "Beat the Dealer" (1962), explaining the system for winning at blackjack he developed based on the mathematical theory of probability. The system worked so well that Las Vegas casinos actually changed the rules of blackjack to give the dealer an added advantage. Those changes would prove to be short-lived, but Thorp's book would go on to become a massive bestseller, and remains a key guide to the game of blackjack to this day.