Nightmares, memories and hallucinations merge unsettlingly with reality, creating a darkly tense, mysterious story. I actually found myself to be quite spooked at some points in the book, with characters involving themselves in Ouja boards and old abandoned lunatic asylums; I know, that makes it sound like a classic, clichè horror story but it's not!
I think the main feature of this story is all the mystery. Right at the very beginning, before the story even starts, we are told "My name is not Mara Dyer, but my lawyer told me I had to choose something." So from the very outset, we are already filled with questions, the biggest one being, 'Who is Mara Dyer???' This question is the foundation of the book, which builds up around it and, bit by bit, gives us fragments of insight into the protagonist's life in order for us to be able to start piecing together the answer. By the end of the book, we do have some answers, but the whole picture still eludes us, leaving us hanging and anticipating the sequel. And the end will leave you inwardly screaming for the next book.
I have already recommended, and passed on, The Unbecoming Of Mara Dyer to one of my friends and I'm recommending it to all of you too!