A cleverly-woven thriller where you're told from the beginning that you're dealing with an unreliable narrator. As with most stories of this type there's an element of having to suspend your disbelief over convenient coincidences and relying on characters to behave in a particular way, but nevertheless you'll be trying to guess what's really going on from the very first page. I'm not sure it entirely holds together if you analyse it closely, but you'll have to decide yourself if that really matters.