First off I just have to say that I absolutely loved the character of Amy - she is bitter and exceptionally devious, yet somehow I found myself liking her. Not someone you could trust with anything but I bet she is a riot on a boozy night out. Nick I found to be far less likeable and although the author tries to manipulate us in to having sympathy for this man in the beginning he always came across to me as quite weak and personality-less. I think it helps that although I am late to reading the book I have not watched the film - in fact I actively avoided it as the book is usually better anyway. I am at a loss to see how this book could be made in to a film that captures every nuance and that can engender the same level of threat and anguish you feel from the book.
Although there is the theme of an investigation in to the missing Amy, the police seem to write her off as dead very early on and I did wonder if such a knee jerk reaction was typical - but this is fiction so I didn't dwell too closely on it. I did enjoy the way the investigation slithers through the tale as though it is another character in it's own right. This allows much more flexibility within the plot structure to misdirect the reader but also to enlighten them, quite a literary juggling act.
The plot and it's pacing were spot on for me, I just found that some of scenes in the Control Centre for co-ordinating the search for Amy where a little unnecessary and added a needless distraction from the central tale. It also felt strangely like an old-fashioned morality tale, the moral in this one being "everybody lies to others and, most of all, to themselves". It also felt a little unfinished, just tapering off to a nothing of an ending which, I suppose, gives scope for a follow up novel or just allows the reader to make their own mind up about what happens next.
I thoroughly enjoyed this book and became absorbed by what these damaged people would do next - both to others and to themselves.