Math For Everyone by Heinrich Grothendieck

Games have always been a part of man's life, but perhaps at the end of the previous millennium, we realized their importance mainly because of politics and economics.
When two large companies fight to win buyers, they establish a game. Obviously, the more buyers a company has, the greater its profit. So on a daily basis they use strategies to win buyers. A common example is "bidding" where they lower the prices of certain products for a while, looking to attract more buyers. But think about it, if a company uses this strategy, the other company can't just sit back and do nothing, so it will be forced to counteract the other company's move. In other words, a game is established between them.
The same thing happens in politics when several opponents look for the population to vote for them, each one performs a strategy seeking to obtain the largest number of voters.
If you think about it a little, you will see that games are in your daily life. When you are looking for a strategy to make your time at work as short as possible (you are competing against others who are looking for the same thing and can affect your commute to work), when you want to "force" your children to do housework, when you are thinking about negotiating a salary increase, and so on.
The purpose of this book is to introduce you to the world of games, but from a formal perspective. We will start by looking at examples of games and strategies for winning them, and then formalize these definitions in chapters 2 and 3.