More mad Culture fun, this time involving a sci-fi Rapture and the complications attending when a deep dark secret, only not really, threatens to come out making life very difficult for people and ships alike. A lot of this is about life and death, immortality and afterlife and meaning and the things you do to pass the time between birth and death and why you even bother, making the whole thing almost painfully poignant and significant as it turned out to be the last Culture novel and the next-to-last Banks novel. This is incredibly sad and at the same time it has all the magnificent bravura, panache, energy and utter disregard for scale that you want from a truly popping space opera with big visionary ideas and brain-melting scenery and blistering action and scathing dialogue between god-like machines and yet the same old fears about life and death and the meaning of it all no matter what the scale. You don't want it to stop. Then it stops.