I've read the whole series of Martin Beck books now, and it's certainly been an enjoyable one. Despite being the finale, this is not the strongest book in the series, but it's by no means a bad story - with one or two exceptions.
**WARNING! SPOILERS**
The plus points of this story are:
1)it's an exciting read, like the rest of the Martin Beck books, and there is genuine suspense in the detectives' struggle to combat the titular terrorists
2)the story features Gunvald Larsson a great deal, and he really is a very entertaining character - his snarkiness certainly made me laugh few times
3)Martin Beck finally gets a decent home life and as close to a happy ending as it's possible for a character like him to get, even if his other half Rhea does come across as somewhat of a Mary Sue at times.
However, for me there are some major flaws with this book, not the least of which is the blatant political tone of the narration. Yes, we all know that Sjöwall and Wahlöö had strong Communist sympathies at the time, but did they really have to make it so obvious in this novel? The tone of the narration is quite preachy at times, and this quickly gets tiresome. Secondly, there are too many plots in this book, one of which has no bearing at all on the main story, and the other? Well... This leads on to what was for me the third major problem with this book: the storyline involving the character of Rebekah Lind. We are supposed to feel sorry for this pitiful girl and to sympathise with her assassination(!) of the Swedish Prime Minister, but the only feelings I had toward her were anger and frustration. Maybe that makes me cold and heartless, but I thought that particular character and plot line were unnecessary and my disbelief and annoyance threw me completely out of the story. Also, knowing what we know now about the real life assassination of Olof Palme, these scenes were difficult to read.
In conclusion, then, I gave this installment 4 out of 5, mainly because the main plot is so good and I enjoyed the characters of Gunvald Larsson and Martin Beck so much. However, as the finale to this excellent series of novels it could have been better. Frankly, and it pains me to say this, if you stopped reading at book 9 (Cop Killer) you wouldn't be missing out on too much.