There are a few aspects of this book that I clicked with and a few that prevented me from really liking it. Overall, I would say it's an above average thriller and would recommend it to fans of the genre. I listened to the audiobook, and I found it well read.

The unreliable narrator was well done, especially in the beginning. You can clearly pick out inconsistencies in her perception of events. That coupled with her voyeuristic personality is engrossing. I wish this had come into play more in the final showdown. If she was forced to question her understanding of reality more. 

The ending, while interesting, didn't completely satisfy. I felt like it was missing something. And I really don't understand the final story told to the cops. Why would you need to lie? How was it not self-defense already? Is this a UK thing? When someone tries to murder you here, you can fight back. Although if this took place in America, it would not make any sense for her to go to the cops to help the case in the first place. It would have been as good as a false confession. They would have known she took the train and was in the area the night of the murder. The cops would also be questioning Tom, as well. A man who recently left his wife for his mistress. Then the nanny ends up dead. He would at least be in the mix of possible suspects. Poor police work here, in my opinion.