This is part of “The Culture” series, a “non-linear” science fiction series; i.e. the books are set in a particular background, but the series can be read in any order. The Culture is a vast civilization distributed throughout our galaxy, largely run by intelligent machines. The “Player of Games” is Gurgeh, a man who has specialized in gaming and game theory for decades. But he is getting so bored, he is tempted to cheat at games just to keep his excitement level up. He is asked to go to a rival civilization, the Azad Empire, to take part in the game of Azad, which is the center of their culture. The winners of the game become the Emperor and other leaders of the Empire.
The novel becomes both a political thriller and a thought piece about the obsessions of competition, especially when winning or losing is a life and death matter. It’s an excellent novel, with a deeply thought out main character, and constant tension, even when it seems not much is happening. (A LOT is happening, even though Gurgeh often misses the implications.)