This series has gotten so deftly episodic that I don't have much to say about it. Ordinary-looking cases turn up, and then they turn out to have slightly non-ordinary elements about them, and then they turn out to be tied into supernatural threads running back through decades of London history. And then plot happens. Several of our continuing main characters are involved.
(Second book I've read in a row dealing with a fictional rotten housing estate south of the river. Wonder if there's been something in London news that I missed.)
Peter Grant remains entertaining to read: not just first-person snarky, but first-person nerd snarky. Also rather a sweetheart. Grant doesn't have the undercurrent of bitter self-despite that, say, Vlad Taltos does. (I assumed self-hatred went with the snarky-narrator territory, but no, it turns out not.) He is in some respects rather a cluebag -- as the last bit of the book shows, among other things -- but this is part of the charm. Presumably he will gain bitter experience as the series goes on. Probably have to have a talk with Lesley at some point, and with Beverly, and Nightingale come to think of it... well, we'll see.