Poker is a card game in which players wager money (called chips) against one another. It has many variants, but all of them involve betting and a showdown where the highest hand wins. Although the outcome of any single hand involves considerable chance, players can shape their long-run expectations through actions chosen on the basis of probability calculations, psychology, and game theory.

The game begins with each player putting in an initial forced bet, either the ante or blind bet. The dealer then shuffles the cards and deals them to each player, beginning with the player to his or her immediate left. The cards may be dealt face up or down, depending on the game. During each betting interval, players must place into the pot (a central pot of chips representing money) a number of chips equal to or greater than the amount placed by the player before them.

A player can choose to call a bet made by the player before them, raise their own bet by putting in more chips than the previous player did (raise), or push their cards to the dealer face down without putting any additional chips into the pot (fold). Some players may also attempt to make a hand by bluffing.

Although Poker shares some elements with other card games, it is unique in that it requires a significant degree of skill to play well. This skill relates to the separation between the known and the unknown, the controllable and the uncontrollable. In this regard, Poker is a useful metaphor for life in general.