I bought the Carlucci 3 in 1 book in part on the strength of The Rosetta Codex, in part because my wife likes crime books. The latter motive worked out.
In a gritty, modern San Francisco, an ex-cop and a teenage girl separately look out for a serial killer. There is an SF element to the book, but it's largely a crime story. As SF, it does a fair job describing a depressing near future San Francisco that's separated by class and inhabited by interesting characters. Unfortunately, Russo works a little too hard on painting the picture. Pretty much every time the protagonists turn around, there's another description of a new category of characters. After a while, it's just too much - we get the picture, it's gritty. I don't need to see the details of each particular kind of grit.
Rather than just running description, I would have preferred to see more about how this stratified society actually works. For example, Russo sets up the Tenderloin as a special sector that's hard to get in and out of. But after the first time, characters seem to get in and out with no trouble at all. And with so much of the city seemingly given over to vice and violence, it's hard to see why a special district is needed.
The story itself is a fairly straightforward crime story. It's reasonably well done, but nothing special. The characters are interesting, and the book stays readable, but not hard to put down. At some points, I was reluctant to pick it back up, but that may be because I'm more interested in SF than crime.
All in all, probably worth a read if you're a crime fan who can tolerate SF. Less worthy for SF fans who can tolerate crime.
The problem with describing a depraved society is that the violations need to be even more depraved to be credible. I found Carlucci's Edge to be less satisfying than its prequel. The plot, for one thing, hinged on a situation that was completely unsurprising in the milieu as described. The denouement left me wanting, thinking isn't there more?, even though it had been clear for some time that there wasn't.
The characters themselves were mildly interesting, but not deeply. Russo sets up several close relationships, but they were largely described in a cursory manner, and it was difficult to feel much about them.
The first novel had the benefit of (over-)describing a new and interesting environment. This story, though more involved, is less interesting, and neither engages our interest in the environment, nor sets out a sufficiently intriguing mystery to carry itself.
If you really liked Destroying Angel, or really like crime stories, this is worth a read, but otherwise, pass.
I found this story to be similar to its immediate predecessor, Carlucci's Edge, though with a bit more emotion to it. Russo completes several cycles, in a sense, by finally going further into the Core, and by tying up some loose ends about New Hong Kong.
Fundamentally, however, Edge and Heart were similar - Carlucci chances on a case, encounters resistance, deals with 'slugs', and spends a lot of time in the Tenderloin. His wife and family play a slightly larger role in this book, but while they play a nominally central role, they feel much more like adjuncts than key players.
Overall, a decent police story with a mild SF edge. Russo continues to rely heavily on pass-by descriptions of strange characters than on a fully developed economy or environment, and it shows.
Trilogy as a whole
As I noted at the beginning, I'm an SF reader, not a crime reader. These books are written for the converse audience. For me, they weren't satisfying. The SF trimmings are exactly that - trimmings. While the plot does depend on them in some way, an only slightly modified plot could have taken place in 1850. Russo depends quite a lot on description of outre types and a modern-noir feel, but I never had the feeling that his San Francisco could be a real place. For one thing, despite all the dropping of familiar street names, there's never a sense of the city as a whole, and how it functions on an economic and social level. The focus is always on the bizarre Tenderloin district, but Russo undercuts himself in selling it as isolated but showing that there is virtually unlimited access to it. If it's unclear how the city operates, the same is true of the Tenderloin, and, at the opposite end, of the nation as a whole - it's not even clear what the nation is.
As crime fiction, the stories seem acceptable, though I'm not the best judge. As science fiction, they don't work well. As literature in general, they're passable. It's clear from The Rosetta Codex that Mr. Russo can write fairly well. I don't believe he's done it here.