The Takeshi Kovacs trilogy:
Altered Carbon
Broken Angels
Woken Furies
Then,
Market Forces
And finally,
Black Man
All of which were written by Richard K Morgan. They all use some kind of sci fi premise and all explore questions of social organisation and effective individual violence. The main character in each novel is a mercenary man of some kind, with aggressive instincts, some kind of differentiating skill, but still with lots of questions about the meaning of it all.
Altered Carbon is set in a world where cortical implants make it possible to transfer the complete and current state of your personality from one body to another through a process of up and download. It is of course hugely expensive and has changed the dynamics of the world and what's possible in significant ways. Kovacs, a man with a history of elite soldiering in and out of wartime custom bodies, operates more as a private detective in this story. The result is very sci fi noir. Excellent stuff. Broken Angels features the same universe and the same main character, but events have moved on considerably. In this story Kovacs is back to his old life of mercenary solider, and we learn more about where the current state of the worlds came from. Woken Furies finishes off the Kovacs lifestory by taking him "home". It's weaker in some ways than the other two books, not least because it has a grand new cast of characters that Takeshi used to know and is meeting again, but we've never seen them before, so it gets confusing.
Black Man (or Thirteen in the US) is a different book. Very similar themes, but better written and developed. The author perhaps is getting closer to what he wants to say. The world of the story is our own, but moved on some several hundred years. Where the Kovacs of Altered Carbon is a man trained to use and be part of technology, Carl Marsalis of Black Man is a thirteen, a product of a program of genetic development meant to produce... well, what? That's a large part of the story. The thirteens are part genetic throwback, part advanced development. And of course, soldiers. By the time of the story, the soldiering programs have been disbanded and Carl is a kind of mercenary until he gets brought in as a consultant on the case of another thirteen whose gone more rogue than usual.
Market Forces is a different book again and doesn't fit exactly with these other stories. It's set a much shorter distance into the future and features a world where what we know as the mercenary and competitive nature of corporate employment has become somewhat more directly physical: executives can and do legally compete in aggressively lethal road rage duels for promotion and position. And the banking and finance worlds have expanded into the realms of conflict investment: they finance and manage wars and regimes, and sometimes regime change too. Mad Max meets Greed. Less of a sci fi book too inasmuch as no one in the story is enhanced by anything other than anger or avarice.
Currently reading Beat The Reaper by Josh Bazell. So far it's an "underbelly of hospital residency" story that's quite familiar these days, but the writing is slick and darkly funny, so it could be okay.