Consider Phlebas

The first novel in the Culture series, Consider Phlebas' protagonist is an enemy of the Culture, an Idiran spy. His mission is to retrieve a Culture mind (a sentient machine) that evaded Idiran capture. The real beauty of this novel (beyond the exquisitely layered language, worldbuilding and plot) is that it sets up the reader to view the Culture as a questionable force in the universe, while all the other novels in the series have Culture protagonists! From the get-go to the very end, I found myself disliking the Culture, and yet fascinated by Banks' world. I'll definitely be purchasing the other novels in the series. Cannot recommend enough.