I was straddling a 3 and a 4 in rating this book. While in some ways necessary to build the suspense of the story, at least the first half of the book dragged on for way too long. Cathy's recovery happens pretty quickly as well. She goes from not even being able to think of Lee to confronting & attacking him without hesitation. Seems to be pretty rapid therapy to me. Lastly, while it is not implausible that a psychopathic Lee would return to attack Cathy, as well as her boyfriend and former friend, it does feel a little out there.
The best parts of the book were the places in which we were able to get into the mind of Lee, especially in the way he was able to turn Cathy's friends against her. Watching Lee exercise his power over Cathy & seeing her go from being a strong, independent woman to what she later becomes was also a solid point of the book. One could barely make a connection between what seems to be two completely different women.
Overall, a good book, just a bit too long.