Consider Phlebas, first published in 1987, is a space opera novel by Scottish writer Iain M. Banks. It is the first in a series of novels about an interstellar post-scarcity society called the Culture. The novel revolves around the Idiran–Culture War, and Banks plays on that theme by presenting various microcosms of that conflict. Its protagonist Bora Horza Gobuchul is an enemy of the Culture. Consider Phlebas is Banks's first published science fiction novel, and takes its title from a line in T. S. Eliot's poem The Waste Land. A subsequent Culture novel, Look to Windward (2000), whose title comes from the previous line of the same poem, can be considered a loose follow-up.
This is the second Banks I’ve read and I thought they were both terrific. Unlike some epic, galaxy-spanning space operas, this was pacey, smoothly written with great characters and loads of action and adventure.
The protagonist himself is forgettable -- in fact, he's a shapeshifter. His identity is questionable even to himself. All he has is that he's pretty sure it's better to be biological than mechanical, and that's what seems to hold him together.
However... the world. The Culture. The Mind. The World of the Dead. And dear god, the fight scenes. This is a book that justifiably made space opera interesting, not just by showing an actual war (where all the protagonists know they are eminently disposable) but by showing a world which is clearly and utterly beyond humanity.
