Poker is a game in which players compete for an amount of money or chips contributed by themselves (called the pot). It requires considerable skill to minimize losses with bad hands and maximize winnings with good ones.
The game is played with cards and chips, usually in a betting interval, or round, that lasts until one player has the best five-card hand and wins all the money in the pot. Before a round begins, players place an initial contribution into the pot, called an ante. Depending on the rules of the particular variant, this can be any number of chips. The game may also have a dealer, whose responsibilities include shuffling and dealing the cards. Often, this person is a player, but can be a non-player. The player with the highest hand starts the betting, and each player in turn must either call that bet by putting into the pot the same number of chips as the previous player or raise it by putting in more than the preceding player did. A player who cannot call or raise a bet must drop out of the betting, discarding their hand and leaving no one else to compete for the pot.
Expert poker players are skilled at extracting signal from noise to build models of their opponents’ behavior, and at integrating that information both to exploit them and protect themselves. Their approach, modeled on the 1944 book on mathematical game theory by John von Neumann and Oskar Morgenstern, has applications in areas as diverse as cognitive psychology, decision making, and computer science.