This is one of the most convoluted Culture novels (9 in total plus State of the Art about Earth). I read it awhile ago, but forgot to write about it since I skipped through it as some parts are barely readable, and I suspect the skipping made it even more unreadable.
It is about a mercenary called Zakalwe, who does the dirty work for Special Circumstances, but there are two narratives, one going forward in time, depicting Zakalwe's current mission, and another going backward in time, depicting previous missions and eventually back to his childhood.
To save you the effort, eventually we find out Zakalwe is not Zakalwe, but Elethiomel, Zakalwe's childhood friend who eventually becomes an enemy in a Civil War and murders real Zakalwe's sister Darkcsense, and as if that is not horrible enough, makes a chair from her corpse (the Chairmaker) and sends it to Zakalwe to sit on. Zakalwe kills himself out of grief and Elethiomel is possessed by guild so he takes Zakalwe's name and identity and becomes high-danger mercenary for Culture's Special Circumstances' most dangerous missions, secretly hoping he will die and be released from the constant guilt and regret for being responsible for the death of his childhood's best friend.
It doesn't go that way though, and Zakalwe becomes a highly important asset for SC and the current mission is also very dangerous and he only accepts it if SC can help him find Livueta, real-Zakalwe's last remaining sister. He is wounded in the conclusion of the current mission and SC keeps the promise and brings him to Livueta whom he begs for forgiveness, but she recognizes him as Elethiomel, his brother's and sister's murderer, and does not forgive him and he gets a major brain aneurism from desperation, but still doesn't doe as the SC drone who is there performs emergency surgery and saves his life.
So, the fake Zakalwe is still alive and continues to suffer from his guilt for the murders, and SC goes back to business conducting secret operations, assassinations and coups, as long as the Minds say it is in the best interest of everyone.
I stopped reading Culture novels after this one, since it is very dark and sordid, and yet still with the most incomprehensible names for characters, just because, but Iain Banks seems to have been a great guy, dead of 59 of bladder cancer, which might or might have not been partially caused by his love for Scotch Whisky. He married his nurse 6 months before his death and asked her 'would you do me the honor of becoming my widow?" How cool is that in the face of certain death? So, I will read ALL Culture novels after all.
