Let me begin by saying that the premise of this book is rather intriguing. A woman suffers from both long term and short term memory loss after a terrible accident resulting in each day being new to her. Every morning, Christine wakes up in a home she does not recognize, to a man she doesn't know as her husband, not really knowing who she is and having no recollection of a past beyond her youth. Her husband has gone to extreme lengths to make accommodations for her memory loss and patiently retells her stories any time she has a fleeting glimpse of some past event. As the story progresses, Christine begins keeping a journal and discovers that her husband's stories are full of holes, and thus begins the mystery.
While I liked the idea of Before I Go To Sleep, midway through I found it dragging a bit and even somewhat predictable. Long before the end I knew what was going to happen, which I won't divulge for those who will choose to read it. I also found several problems that made it tough to swallow what happened. Without giving too much away I'll mention that both the relationship with her doctor and the deal with her son just didn't work. In particular, if the doctor had a file on her, which the story indicates he did, then he would have known much earlier about some of the discrepancies.
Overall, it was a decent read and would be great made into movie.