Poker is a card game played by a small group of people around a table. The game is fast paced and players bet continuously until one person has all of the chips or everyone folds. There are various rules about how to bet, including when and how much to raise.

The game is popular in many countries. It was once considered a man’s game, unsuitable to polite or mixed gatherings but after the 1920s its popularity extended to both men and women. It is often thought to be the ancestor of other card games such as Blackjack and Rummy.

In poker there are many mechanisms that allow players to strategically misinform each other about the strength of their hands. This is especially true in online play, where physical cues such as eye contact and body language are eliminated. This makes it particularly important for professional players to be able to read their opponents and extract information from multiple channels.

There is also a large element of chance involved in the game, which makes it an interesting mathematical problem. A famous 1944 book on mathematical game theory by mathematician John von Neumann and economist Oskar Morgenstern included a simplified version of the game of poker as a central example. They proved that a mathematically optimal strategy exists for the game and that bluffing is a crucial part of that strategy. In addition, they showed that there is a maximum amount a player can call when raising, which is known as the limit.