Counting cards in blackjack has become substantially more difficult as a result of casino countermeasures. The most common is the use of more decks, which decreases the player’s advantage, but even in the few remaining single- and double-deck games, dealers will often shuffle prematurely or unusually frequently to defeat a suspected [...]

American mathematician Dr. Edward O. Thorp is considered the father of card counting. His 1962 book Beat the Dealer (ISBN 0394703103) outlined various betting and playing strategies for optimal blackjack play. Although mathematically sound, some of the techniques described no longer apply as casinos took counter-measures (such as no longer dealing [...]

Card counting is a card game strategy used to determine when a player has a probability advantage. The term is used almost exclusively to refer to the tracking of the ratio of high cards to low cards in blackjack, although theoretically card counting can be used in some other card games.
How card [...]