The thesis of Debatable Space by Philip Palmer seems to be that even if humanity were living in a world of unlimited resources humans would nevertheless still choose to enslave each other and default to systems of institutionalised rape and murder. It's sort of an anti-Culture novel in that respect. Mind you the novel is a little uncertain about said unlimited resources and alternates between suggesting that they are only unlimited for the elite because of the underlying slave-based economy and suggesting that they are actually practically unlimited due to siphoning energy from suns, exploiting extra-terrestrial mineral resources and massive scale automated production.
I alternated between enjoying and being largely indifferent to this novel. About half of it is a brutal revenge drama played out by sketchily drawn, mostly rather dull, characters. The other half is a biographical novel about Lena Smith, third oldest human in the universe and mother of the dictator at the heart of the repressive regime. In comparison to all the characters around her, Lena is vibrant, multi-layered, fascinating and frustrating all at once. She is a totally unreliable narrator, beset by insecurities, with numerous axes to grind so we need the other character viewpoints in order to interpret her own account of events; its just a shame that most of them are not even attempting to be as interesting as she is and even the one? that is, is fairly two-dimensional in the end (revenge driven tactical genius) with a few quirks hung off (blues-playing) to make him look better fleshed out.
The book also has a lot of fun with the concept of sub-light speed travel coupled with instantaneous communication: battles take decades to plan because that's how long the fleets take to reach each other, but in the end its world-building is primarily about man's inhumanity to man, not about exploring ideas and worlds are created simply to illustrate the horrific ways we might treat each other given technological advances. Lena Smith is the best thing about the novel, and she's very good, its a shame the same attention wasn't paid to the characters and settings around her.