A couple years ago, when this came out, I read like a paragraph, and then realized I needed to reread the entire Revelation Space sequence (2000-2003), including the Prefect (2007) & Elysium Fire (2018). I haven't at this time reread Chasm City (2001), even tho that's the best book of the series, and the one you should read as an introduction IMO; nor the short story collections. Distraction and scattering in my tsundoku has made that a longer reread than expected. Short review of the series: Mostly great. I got bored rapidly of a lot of Absolution Gap's annoying child who is more than she seems. Scorpio the Hyperpig gets way too much page time. The Prefect books are very cop procedural, in a shitty colonial police force with too many powers over Demarchist citizens. For all the books, I like the tech and setting details, and weird corrupted AIs are always a favorite feature, and body horror/lunatics like The Captain.
Inhibitor Phase (2021) shows a big difference in tone from the decades-earlier books. There's a lot more concern with personal relations, with "feelings"; I don't mean this in the cliché "hard SF fans want equations not emotions" way, just that murderous old Humans & Hyperpigs who haven't previously shown much emotion, explaining themselves to each other, are out of character.
It starts with an isolated colony trying to hide from the Wolves (black cubes, Inhibitors, etc), willing to commit genocide on anyone dumb enough to seek refuge. Miguel, their leader, does not earn much respect from me then, or later when he has to deal with an intruder, or in the hundreds of pages of his whining "I'll keeeeel you!" that follow. "Glass", his captor/guide/nemesis, isn't a lot better, wrapping a few moments of basic humanity in long stretches of emo edgelady transhuman (she's not quite a Conjoiner, but more than most Ultras) contempt for baseline humans. The other people we meet, on or around doomed Yellowstone, are just as terrible; the Pigs aren't as bad, but they don't do much.
Finally halfway thru we get a classic Reynolds heist/assault that goes very wrong. It's… overly familiar. I really should have reread some of the short stories, because I think much of it is in there. There's some deliberately gross torture, the fights are cinematic but not entirely sensible.
The final section's an update of Ararat from Absolution Gap, with unusual behavior from Pattern Jugglers; nothing is explained because nobody knows. Glass and Miguel undergo changes, much as Sylveste and others do in Revelation Space. More interesting outer-space piloting scenes, made easier by the Plot Coupons earlier collected. An alien ship heist at last, and Glass-ish now has too much knowledge. Scorpio/Pinky gets to say "what?" a lot (and I don't think his lifespan and survival at this point is plausible). Another cozy emotional feelings ending.
Most Reynolds I blast thru in a sitting or two, this took many days, I'd often hit a wall of annoyance at feelings or vacation time. Off and on it gets back to the main plot and I'm interested again.
★★★½☆ - unfortunate, since I love the earlier books, and needed more closure than this.
Much of the future from here has been plotted in Galactic North and other short stories, Humans scatter and do well and poorly for a while, with less Wolves on their backs. There's another Prefect book, Machine Vendetta, coming next year, presumably backfilling the end of the Belle Epoque. Hopefully he can stay more on topic?