Very unputdownable, and if it hadn't been for the epilogue I might even have given it a fifth star, but I didn't care for the epilogue at all, and it kinda ruined the rest of the book for me.But ignoring the epilogue this is the psychological thriller genre when it's best. A woman knowing something is wrong, but being made to question herself and even her own sanity by everybody around her as she tries to figure out what is wrong. For a time I worried whether Sophie McKenzie could work out a decent ending, but she actually managed quite nicely on that account.There were parts I didn't find completely realistic, but fortunately it was more a vague unease than actually asking me to suspend my disbelief altogether. I still don't really see something like this happening IRL though.A thrilling book. I just wish she hadn't added (or I hadn't read) the last 2 pages.