In casual play, the right to deal a hand typically rotates among the players and is marked by a token called a 'dealer' button (or "buck"). In a casino, a house dealer handles the cards for each hand, but the button (typically a white plastic disk) is rotated clockwise among the players to indicate a nominal dealer to determine the order of betting.

The history of poker is a matter of debate. One of the earliest known games to incorporate betting, hand rankings, and bluffing was the 15th century German game Pochspiel. Poker closely resembles the Persian game of as nas, though there is no specific description of as nas prior to 1890. In the 1937 edition of Foster's Complete Hoyle, R. F. Foster declared: "the game of poker, as first played in the United States, five cards to each player from a twenty-card pack, is undoubtedly the Persian game of as nas." .

The fundamental theorem of poker is a principle first articulated by David Sklansky that he believes expresses the essential nature of poker as a game of decision-making in the face of incomplete information.

The relationship between pot odds and odds of winning is one of the most important concepts in poker strategy. Pot odds are the ratio of the size of the pot to the size of the bet required to stay in the pot. For example, if a player must call $10 for a chance to win a $40 pot (not including his $10 call), his pot odds are 4-to-1. To have a positive expectation, a player's odds of winning must be better than his pot odds.

By employing deception, a poker player hopes to induce his opponent(s) to act differently than they would if they could see his cards. Bluffing is a form of deception to induce opponents to fold superior hands. If opponents observe that a player never bluffs, they won't call his bets unless they have very good hands. Slow-playing is deceptive play in poker that is roughly the opposite of bluffing: betting weakly with a strong holding rather than betting strongly with a weak one. If opponents observe that a player never slow plays, they can pounce at any sign of weakness.

Position in poker refers to the order in which players are seated around the table and the related poker strategy implications. Players who act first are in "early position"; players who act later are in "late position". A player "has position" on opponents acting before him and is "out of position" to opponents acting after him. Because players act in clockwise order, a player "has position" on opponents seated to his right, except when the opponent has the button and certain cases in the first betting round of games with blinds.

Unlike calling, raising has an extra way to win: opponents may fold. An opening bet may be considered a raise from a strategy perspective. David Sklansky gives seven reasons for raising, summarized below.

    * To get more money in the pot when a player has the best hand: If a player has the best hand, raising for value enables him to win a bigger pot.

There are several reasons for calling a bet or raise, summarized below.

* To see more cards: With a drawing hand, a player may be receiving the correct pot odds with the call to see more cards.

* To limit loss in equity: Calling may be appropriate when a player has adequate pot odds to call but will lose equity on money contributed to the pot.

* To avoid a re-raise: Only calling (and not raising) denies the original bettor the option of re-raising.

In the game of poker, opens and raises are considered aggressive plays, while calls and checks are considered passive (though a check-raise would be considered a very aggressive play). It is said that "aggression has its own value", meaning that often aggressive plays can make money with weak hands because of bluff value. In general, opponents must respond to aggressive play by playing more loosely, which offers more opportunities to make mistakes.

In the card game of poker, to bluff is to bet or raise with an inferior hand. This is useful because it can cause other players to believe the bluffing player has a dominant hand, so that they all fold; the bluffing player then wins the pot. By extension, the terms are often used outside the context of poker to describe the acts of pretending knowledge one does not have, or making threats one cannot execute.

Pure bluff