As a thriller, it's not all bad - I genuinely didn't know who the killer would be until I had a third of the book left. The plot itself was quite clever, although there were maybe too many red herrings - with culprits being found who ended up not being the right person, etc. 

What really ruined the book for me was the misogyny, and despite the theme (the serial killer only kills women, for a very specific reason) it was not the only reason for it. There's just now redeemable character there. The women are either victims (of the serial killer), or props. They are always somewhat mysterious, sexy, and every interaction between them and the main character involves some sort of sexual tension - mostly on the part of the hero, Harry Hole, as what the female characters think... we just don't know. It became so much that it was kind of gross - every time a female character appears, there's a neat paragraph on the male's character's dick, her legs, what he would do to her. 

I read very few male authors - in fact, I try and avoid them unless I am sure that I won't be absolutely disgusted when I read them, but I craved a thriller like I do every time come late December. This reminded me exactly just why I normally stick to female writers.