For me this was more like 3.75 but since there is no such rating will round it to 4.
I am not that knowledgeable when it comes to Corvus Belli's Infinity Human Sphere universe, so I must have missed some key elements here. But this did not affect the overall experience.
So, in this universe, humanity is split into several domains (totality of them called Human Sphere - some frontier, wild-west, worlds, other highly technological) majority of which are controlled by enigmatic ALEPH AI and his enforcers (think of it as a more action oriented Bank's Culture, or (maybe better comparison) as (even) more action oriented Asher's Polity), of course benevolently (khm) and so called Nomads, three colony ship-nations that are outside the ALEPHs direct control. All of the domains are connected through space-lanes (in lack of better description) that are of course under control of ALEPH (through organizations like O-12). And of course all of human domains love each other so much they are in constant conflict (overt or covert).
So when surprise cyber attack cripples Human Sphere's financials markets everybody is more than willing to point to Nomads as culprits. This is beginning of the story.
What follows is an action adventure that includes ALEPHs operators that get redirected to investigate the cyber attack while they are on one of the Nomads' ships (working deep undercover since Nomads do not like neither ALEPH nor its enforcers), heavily armed organized crime groups (so called maras), unwitting group of heroes, newly formed mercenary group that tries to find its place in highly militarized Nomads' troubleshooting market, and mysterious attackers that are so difficult to identify in already very ...... weird? ...... hodgepodge called Nomad society.
Author's style is good, story flows well (except that first chapter with Midhat finding himself in the wild west styl of cyberspace - that one was like ???? first 2 or 3 pages) and it is full of twists and action. Characters are also not neglected. Only thing I am not OK with is constant I-trust-dont-trust-I-am-anxious-am-I-anxious thought process. This made some of the characters very very difficult (Cruz, I am looking at you), to the point I would not trust them with anything, let alone participating (and especially leading anyone) in deadly conflict. They are so oh-angst-riddden-youth characters that I would slap them right and left if they were actually standing in front of me.
Now I am not sure if this was over-exaggeration due to existing lore, but this was only element I had truly problem with.
Story on its own is nothing complex. Pretty good action adventure with likeable characters. If you enjoy stories like Gray Man, or some newer Tom Clancy novels, I think you will enjoy it. In any case don't expect anything near Culture (or even early-Polity) level of plots.
Editing is good, considering that there are just few novels set in this universe, with few slightly confusing action set pieces (like investigation of cult location on Bakunin). While there is mention of technology and weapons (again, as expected since universe is basis for miniature wargame) they are not dominant nor carriers of the narration. And I liked this a lot.
Humanity presented in novel is for all means and purposes copy of our own times- West and East blocks, and everything in between with, plus what you might call globalist force (ALEPH) working in the background, and manipulating everyone (of course benevolently...... khm). Names are all over the place - Hispanic, North African, even from Balkan area (this had me like, huh?). Antagonists are also very original, especially when one considers their actions - pretty smart and I have to say, for a genre in question, pretty realistic. Reminded me a lot of X-COM (but again not that strange since Infinity table top game is very similar to X-COM).
Overall very interesting book, I am now on lookout for other novels in same setting. If you know more about Infinity and Human Sphere, you will enjoy it more. If you dont (as was case with me) it is not difficult to get involved (lots of things are explained as story progresses).
For an SF action novel, very good. Definitely recommended to fans of action adventure.