Poker is a card game that involves betting and the exchange of information. It started as a game of chance but was soon augmented with elements of skill. Around the Civil War, innovations in poker helped it become a popular game in the United States and other countries. The game has many variants, but the most popular is Texas hold’em.

While the majority of a good poker book is theory, it should also have plenty of practical examples. One way to do this is to keep a file of poker hands that are relevant to the subject matter. These can be hands you have played or those from another source. You can then use these hands as illustrations when discussing the theory of poker strategy.

One of the most important concepts to understand in poker is risk versus reward. This is a concept that is applied to both the game of poker and life in general. It helps you decide whether a particular play is profitable or not. You can find out your odds by analyzing the cards in your hand or by calculating them based on the bets of other players.

Another important aspect of poker is learning to read your opponents. This is more difficult in the online game than in a live game, but it can be done by studying how other players react to their cards. You can also learn from their body language and other physical tells.