This ended up being a three and a half star read for me, mostly because it had more filler than it needed. I can appreciate solid character development and a slow build plot, but I don't want to be bored while reading a mystery, and at certain points in the story, that's what happened (can we just axe the bits about Charlotte? I get that Strike is complex and wounded and that Charlotte is a big part of what his life is, but I just don't give a shit about her. Same goes for Matthew, really.)
The last fifth of the book was really the saving grace here. Until that point I was getting desperate with the sluggish pace and then suddenly everything was revealed in a couple of dozen pages. Basically what I'm saying is - this was a good story and the ending was great, the author just took around 200 pages too many to get there.