I found Before I Go to sleep very thrilling. What inspired you to write it?
I had the idea for the book when I read an obituary of a man called Henry Gustav Molaison. He had died in 2008 but, since undergoing surgery for epilepsy in 1953, had been unable to form new memories He lived constantly in the past. I was struck immediately by a mental image of a woman looking in a bathroom mirror in a strange house to find that she'd become a middle-aged woman, and the house was her home. I couldn't stop thinking about it, and realised that through her story I could explore lots of the issues I’d been thinking about for a while.