The Nightmare Stacks
I was a little bit disappointed with last year's The Annihilation Score. When you switch viewpoint characters in a long-running series, you have the chance to do something new and different, and The Annihilation Scores kinda didn't. The Nightmare Stacks, to a pretty fair extent, does.
Oh, it's got what you expect from a Laundry Files novel. It's got black humor and genuine horror and snappy dialog and imagination and stuff. It's also got some new elements. For example, our new viewpoint character Alex is both a nerdy young guy and a powerful though newly-minted vampire--sorry, victim of PHANG Syndrome--and he's trying to reconcile the two. Also, even more than in The Annihilation Score, the world of the The Annihilation Score has very definitively diverged from our own, which makes for a different reading experience as well. The antagonists are very well written, the bad parts are appropriately sobering, and the ending is a real twist.
In an odd way, this is one of the more . . . hopeful books in the series. Yes, we're deep in CASE NIGHTMARE GREEN where REDACTED and REDACTED cause a disastrous REDACTED REDACTED REDACTED. On the other hand, our guys get to encounter an menace that isn't immune to bullets. In fact, the good guys are pretty effectual!
I'll also note that the book is kindly dedicated to the late great Sir Terry Pratchett. It's a very appropriate tribute, in part because The Nightmare Stacks (even more than 2014's The Rhesus Chart) can be read seen as a Strossified riff on a theme that Pratchett also used.
If you like the series, you'll like The Nightmare Stacks--in fact, I think you'll like it a lot. If you're unfamiliar with the series, this isn't a bad place to start. There are minor spoilers for some of the recent books, but nothing earth-shattering, and Alex is a good introductory viewpoint character.