Well-written and engaging, with intriguing characters and a lot of drama.
However, a lot of the intrigue comes purely from it being written backwards - the book is split into 3 parts, starting out in 1947, then 1944, then ending in 1941 - it feels contrived and frustrating, for it to constantly refer to things the characters know that it is deliberately not telling you. It also has the bonus effect of making it feel like it doesn't have a proper end. If you were wondering what was going to happen to the characters in the first part you were reading, you're screwed, it never goes back to the 'present day'. It sets you up with a lot of drama, then goes through the backstory of the drama, but never /resolves/ the drama.
In short, I enjoyed reading this book until it finished, and then felt cheated due to the lack of a conclusion and denouement.