An intriguing story

I borrowed the book "The Thirteenth Tale" by Diane Setterfield from a friend. At the time, I was unsure if I'd like it. But just a few pages in, and I was hooked.
 
The story focuses on a girl who's hand-picked to tell the true biography of a well-known author. Most of the story is this author's interesting, parentless childhood. It's the story of the author and her twin and how they were raised by the nearly-blind maid and the aging groundskeeper on the family's huge estate.
 
There are sggestions that the girls aren't completely "right" and that maybe they were born out of incest.
 
As the story progresses, we learn more about the biographer's own demon's as she is learning the mystery of the author and her family.  The twist at the end is definitely one I didn't see coming, an dI have to say there is absolutely nothing predictable about this book.
 
Setterfield keeps the story moving, even in the transitions between flashbacks and real time. There are tons of sub-plots in this book that help move the book toward the unveiling of the big mystery at the end, and Setterfield makes sure that none of these sub-plots are neglected.
 
It's easily the best book I've read in the last year. 
 
I'll be looking for new books to read soon, so tell me what was the best book you've read in the last year?