This is about.... about the player of games. Cards, stones? Popup figures, like Risk or Monopoly? On a board, like 3D-Chess. And maybe on more boards. Well, Banks describes the games in the vaguest of terms, so no help there. And it's not that interesting as well, to be honest.
The book is about a confrontation between an idealistic future - The Culture - and the current time. That is: translated into a galactic empire in a Magellanic cloud far, far away. Dysfunctional, brutal, obsessed with personal status.
But wait. What about Jernau Gurgeh's Culture, the player of games and his robotic friends? So his environment isn't scarred with inequality, senseless brutality and idiotic power play. Is it? What about all those AI robots swirling around, from floating buddies to intergalactic star ships? Maybe everyone is equal and free in The Culture, but some are more equal than others. Like the automatons manipulating everything - in exchange for a lethargic eternal peace. Maybe there's no senseless brutality, but cunning at the cost of human freedom is aplenty.
The story is a bit (in fact, very) predictable and reminded me of Ender's Game. And you wonder: besides the AI trickery, what has really changed? In both The Culture and that faraway galaxy?
The book left me unsatisfied. The story is often a dull description of a game. A game we don't understand because it isn't explained. It's just a lot of words describing something that might be interesting. Or might not, we will never know. The only interesting parts are the undercover meetings of the protagonist with the alien society he ends up in.
Compare Banks with Jack Vance. Vance could describe weird societies that started to live before your own eyes. In this book Banks wasn't able to do so. And that leaves us with an uninteresting and predictable story. Man plays games. Is very good at it. Gets manipulated into traveling - with old fashioned despicable blackmail. Plays a life-to-the-death game. Wins. And then it turns out to be more than just a local game. He is surprised. We are not. He goes back home. Says hello to his old friends. The end.