Before I Go To Sleep, by S.J. Watson. Harper, 2011.
Imagine that, because of a tragic accident, you are unable to retain new memories. That is, the memory of everything that you do today and of what happens to you today will be gone tomorrow. Imagine this condition continuing for 20 years!
Christine doesn't know how the old woman in her mirror could possibly be herself, and has to be re-instructed every morning that the man in her bed is no stranger, but Ben, her husband of 22 years. She has no memory of the journal she's been keeping recently, but is dependent on her doctor's daily phone call reminding her of its existence and location. Nor does she know why the note in the front of the journal warns, "Don't trust Ben."
By reviewing the previous journal entries through Christine's eyes and reading the new ones as she writes them, we - and Christine - gradually piece together the story of the accident that caused her amnesia and the chilling secret she ultimately discovers.
This is a great discussion book on many levels: the frustrations of an amnesia victim, the use of the journal and of time passing to advance the plot, the ethics of manipulating the world of the victim, and the completely unexpected climax.