It is a nice idea, two separate lives that are connected flimsily by letters to each other even though they are complete strangers. However it was terrible delivery. The amateur editor inside of me has been screaming with this book. Change in character perspective every few lines. Ahhh! Lack of description, what the hell am I meant to be picturing? Ahhh! Lack of narrative push. Ahhh! A part of the odd interesting line, this story is far from satisfying. It just had no life to it.
Never judge a book by its cover, you're paying for clever marketing.