Her Fearful Symmetry: A Novel - http://www.goodreads.com/review...
I did not like the supernatural aspect of this book. The many issues and secrets surrounding the two sets of identical twins were intriguing, and I would have preferred if Niffenegger had just delved into those further — the supernatural part was unnecessary and just spoiled it. I would recommend saving yourself frustration by skipping this book. - Lani