Not the best of the Culture books by a long shot, though it's an interesting addition. I enjoyed the atmosphere of menace and mistrust that builds through the book, and the focus given to all the non-human minds fleshes the Culture out nicely, but the story felt overambitious and overloaded. At times it was seriously hard to follow which of the amusingly-named ships were doing what, with whom, under which pretenses, and after a well-paced build-up for about 3/4 of the book, the last few chapters pulled together a little too quickly to be satisfying.