All I ask for with each successive Culture book is that he provide some new doozy of a setting in which a new cast of advanced beings can have their conflicts, and he certainly delivers in this one. The main characters are from a premodern civilization inhabiting part of a four-dimensional artificial world and, in a first for the series, they are fully aware of the more advanced aliens all around them. This was a welcome new way to have protagonists with relatable perspectives learn about all the incomprehensible things happening around and to them. And the climactic battle was surprisingly well-staged.