Poker is a card game in which players compete against each other. Players wager money or chips, called the pot, on the outcome of the hand. The game combines luck and skill; it also has a strong psychology element.

The game can be played with fixed or variable limits, and the rules of each variation differ. Almost all poker games involve betting. Players can call, raise, or fold. If they raise, they must bet the amount of money or chips that they have already put in play.

In poker club environments, tournaments, and some casinos, a professional dealer is used, and the player’s position is marked by a round disc (known as a “button”). In some countries, it is illegal for private citizens to operate a poker room, so these environments are usually run by organizations that charge their players either an hourly fee to rent their tables, or they “rake” a small percentage of each pot.

The most popular variant of poker is Texas hold’em, which replaced seven-card stud as the dominant form of poker during the 2000s, after being made famous by televising the World Series of Poker and other events. Doyle Brunson’s revolutionary book Super/System was published in 1978, and is widely credited with revolutionizing poker strategy. In 1983 Al Alvarez published The Biggest Game in Town, a book about the 1981 World Series of Poker that brought Texas hold’em to a wider audience. This book started the genre of poker literature and is cited as one of the most influential works on poker strategy.