Consider Phlebas by Iain M Banks
Consider Phlebas is one of Banks' Culture novels. It is set in a far future of galactic civilizations, artificial worlds the size of planets, the Culture as a post-scarcity quasi-anarchistic society, etc. We see some of this along the way. However, although this is “a Culture book,” the Culture itself is off-stage – only referred to and represented by a single (secondary) character. Most of the book's events are in the figurative back streets of such a galaxy.
The story takes place within the context of a vast interstellar war between the Idiran and the Culture. The Idirans are expanding and have forced the Culture to respond. The book only shows us bits of the war around the edges. It focuses on Horza, a non-Idiran, who has sided with the Idirans because he objects to the Culture's dependence on AI's and other tech. Circumstances lead Horza to be on a pirate starship for a quarter of the book. Even after Horza gets back to working on his assignment, it is on an obscure planet which is outside the area of combat between Culture and Idirans. So, this is not what one usually thinks of as military SF.
This is a space opera. As far as my tastes are concerned, I would say the plot is somewhat analogous to the following. Imagine a story in the Star Wars universe. The central character, Horza, has personal beliefs that make him feel he has greater differences with the Rebellion than with the Empire. So he chooses to do assignments to assist the Empire. The Empire assigns him to go to an obscure planet to capture an advanced piece of Rebellion technology. Horza encounters difficulties getting there and ends up spending a quarter of the book working for a group of space pirates / mercenaries. Eventually, he is able to go to the obscure planet with some of the mercenaries. In the meantime, some Imperial Troopers have attempted to seize the planet. Only a few of the troopers survived and have few weapons or equipment. The last quarter of the book centers around conflict between the troopers (who don't believe Horza is working for the Empire) and Horza (and a few mercenaries).
This analogy isn't perfect. In Star Wars, the Empire and the Rebellion are basically different factions within the same interstellar civilization vying to take that civilization on different paths. The two opposing sides in Consider Phlebas are different civilizations that originated with different species in different parts of the galaxy. And so on.
I'm not a reader of Star Wars books - interstellar good guys fighting interstellar bad guys is not my favorite subgenres of SF. Even though Horza is more misguided than a bad person, having the central character working for the bad guys doesn't make it any more appealing to me. We do get to see some of the far future technology, but all the time spent in out-of-the-way and not-as-hi-tech parts of the galaxy reduced its appeal as a view of the far future. The fact that the impressive Culture civilization is mostly off-stage in the book reduced its appeal as a view of a post-scarcity interstellar civilization. Readers of hard SF may not find all the tech convincing. Although some of the tech is incredible and the story is about a man who chooses the wrong course, I wouldn't call this "idea SF". So, it really wasn't the type of book that is best suited to me.
On the other hand; the pace of the book was good, it wasn't too predictable, it kept my interest, didn't seem too formula-based and wasn't blatantly like other books I've read. (Perhaps, those who read more books of this subgenre might see greater resemblance to other books.) It's not so much my intention to say this is a poorly-written book, but it may not fit the needs of readers similar to me.
It occurred to me that some readers might view this in the context of “For lack of a nail, the shoe was lost. For lack of a shoe, the horse was lost…” If there are readers who would be interested in reading a novel about what might be to some degree a figurative nail, perhaps they would appreciate that part of this story.
Of Banks' Culture books, I've only read Inversions and Consider Phlebas. Outside of those books I've heard about The Culture. However, the books I've read were not set in the Culture and otherwise gave only an outsider's general view of it. Perhaps, I've just managed to read the only two books in the series that are like this - but it has made me wonder why there is a "Culture series" if "The Culture" is always something "over there" that your hear gossip about.