Matter by Iain M. Banks
“Even galaxy-spanning anarchist utopias of stupefying full-spectrum civilisational power have turf wars within their unacknowledged militaries.”
This was an incredible Culture novel. Iaian M. Banks still manages to surprise me a little in each new iteration of The Culture series. In this book, we follow the fortunes of the royal court of a low-tech civilization, the Sarl, at war with another similar sort of civilization, Deldeyn. While this sounds rather hum drum, we later learn that these civilizations are on separate levels of a shell world, Sursamen, a mechanical planet with multiple layers all overseen by other more technologically developed civilizations. The conflict is first about the succession of the king, and the war effort. Then it changes once the sister of the successor to the king gets involved, and guess what, she's part of Special Circumstances.
This was a long setup for a short battle at the end. It wasn't the most satisfying ending I could've imagined. The whole effort seemed a bit rushed when we got near the end, but the setup was wonderful. If you like getting lost in the details of the civilizations, and races of The Culture, you will like this novel. If you are easily confused by complicated names of many different aliens, this one will most likely leave you scratching your head.