The history of poker is a matter of some debate. The name of the game likely descended from the French poque, which descended from the German pochen ('to knock'), but it is not clear whether the games named by those terms were the real origins of poker. It closely resembles the Persian game of as nas, and may have been taught to French settlers in New Orleans by Persian sailors.
It is commonly regarded as sharing ancestry with the Renaissance game of primero and the French brelan. The English game brag (earlier bragg) clearly descended from brelan and incorporated bluffing (though the concept was known in other games by that time). It is quite possible that all of these earlier games influenced the development of poker as it exists now.
English actor Joseph Crowell described Poker History, the game as played in New Orleans in 1829: played with a deck of 20 cards, four players bet on which player's hand of cards was the most valuable. Jonathan H. Green's book An Exposure of the Arts and Miseries of Gambling (G. B. Zieber, Philadelphia, 1843) described the spread of the game from there to the rest of the country by Mississippi riverboats, on which gambling was a common pastime.
Soon after this spread, the full 52-card English deck was used, and the flush was introduced. During the American Civil War, many additions were made, including draw poker, stud poker (the five-card variant), and the straight. Further American developments followed, such as the wild card (around 1875), lowball and split-pot poker (around 1900), and community card poker games (around 1925). Spread of the game to other countries, particularly in Asia, is often attributed to the U.S. military.
The game and jargon of poker have become important parts of American culture and English culture. Such phrases as ace in the hole, beats me, blue chip, call the bluff, cash in, pass the buck, poker face, stack up, up the ante, when the chips are down, wild card, and others are used in everyday conversation even by those unaware of their origins at the poker table.
Modern tournament play became popular in American casinos after the World Series of Poker began in 1970. It was also during that decade that the first serious strategy books appeared, notably The Theory of Poker by David Sklansky, Super System by Doyle Brunson, and The Book of Tells by Mike Caro (ISBN 0897461002). Broadcast of poker tournaments for cable and satellite TV distribution, such as with the World Poker Tour, has added additional popularity to the game, as has the introduction of online poker.