Perhaps the weakest of the Culture books in my opinion (and this is reflected in its low overall score on here). I think this may be because there is not actually a lot of Culture in it.
The set-up is a third person narrative of one Culture agent embedded in one feudal culture on a backward world, twinned with a first person narrative detailing the story of another Culture agent in a competing feudal culture on the same world. The link being that these two agents represent different approaches to how the Culture intervenes in these types of societies.
So far, so good but this really just ends up being two tales of fantasy feudal cultures with nothing really new setting them apart from any other fantasy tale. Maybe I am being dim and there is something incredibly clever going on here but I do recall that this was largely how I felt the last time I read this (circa 2000 or so).
High quality writing and clever use of the perspectives make the book engaging enough to be 4 stars but I can only really recommend this one for Culture completists, I am afraid.