This is the latest Matt Scudder novel from Lawrence Block. I'm a longtime fan of both the author and this series, so it was a must. It's very "gritty" with quite a bit of violence, including sexual violence, including pedophilic sexual violence, explicitly described from the perpetrator's POV. So: not recommended if that's going to put you off your feed; it seems more graphic in this regard than previous Scudders but I might be just getting old and easily shocked. And it builds to an unusually harrowing climax.
Just to show you how much I'm into the series: I worry sometimes whether enough crap will fall on Scudder to make him start drinking again. (Hey, maybe that happens in this book. I'm not going to spoil it for you.)
And Scudder, I think, is probably the best fictional detective in the business, amazingly diligent at picking up clues and following them to the bad guy when nobody else can. I swear, Matt could find Osama if they put him on the case. And if Matt weren't, um, fictional.
For what it's worth: I picked out the bad guy right away, once an important clue was provided. You can too, if you pay attention.