All through this book I really hated the psychotic villain and seriously intended to give the book 2 stars (and that only for the impeccable writing style).
The finale altered it all. So brilliant that it's impossible not to admire it. The villain is still twisted and maniacal, but the book is great. As the plot is resolved, the whole picture comes together in a way that I honestly never encountered, even in the best mystery novels. The reader is just forced to reappraise all his views and guesses, right or wrong (yes, I did get some of the guesses right!), and finally to admit that, however evil, the main character can be understood.