From the author's Q & A at the Guardian:
How did you come to write Before I Go To Sleep?--Marshal Zeringue
I was reading about a man called Henry Molaison who suffered severe amnesia following an operation he underwent when he was 27. He died at the age of 82, and for all that time could form no new memories. I was struck by the image of that old man waking up and looking in the mirror, fully expecting a 27-year-old to be gazing back at him. I realised how vital our memories are to our sense of self, and from that seed the whole novel began to grow.
What was most difficult about it?
I decided to tell the story in the first person, from the point of view of someone who has severe amnesia. That presented some tricky technical challenges, particularly as I edited the book. I had to keep a close eye on the things my character knew at any given time, and the things she didn't.
What did you most enjoy?
The whole process was...[read on]