Anyone who thinks Dan Brown can make a smart thriller has never read Charles Stross. It’s a world where demons and magic can be called forth from parallel realms using math, computer simulations, and the occasional sacrifice.
It’s very clever to the point where I occasionally had trouble following exactly how we got from A to B. I was never totally lost but I regularly realized I didn’t know what they were talking about, shrugged, went with it. That definitely took away some of my enjoyment. I understood the plot but thought it could do with a bit more exposition.
I’d give it a 3 out of 5. I enjoyed it and I’ll come back to the series but a good bit of the world building ‘magic’ was completely over my head. If you’re into math, programming, physics, or possibly law (my 2 friends who love this series are lawyers), this is right up your alley.