It's a novel by Iain M. Banks but it's not set in the Culture universe. It's set in a multiverse. I wasn't into it.
I have a tough time with multiverse novels. So there's an infinite number of universes. Sandy in Universe A "jumps" to Universe B. Since there are an infinite number of universes "similar" to Universe A, each with its own Sandy-similar... how come, in these stories, exactly one Sandy arrives? Why not a dozen?
That's not Banks' fault. But my multiverse grumbling distracted me from appreciating characters, plot, etc.