Picoults says in the notes of the book that this is her favourite book so far & I have to say I agree - This book is a huge leap away from Picoults usual scenario of family/court drama, which I have always enjoyed, but this is by far her best.
The story centers around 1 guy who after losing the love of his life in a car accident spends time searching for her ghost, he goes on a journey of personal discovery & somehow his life becomes entangled with Lia - a woman who died in 1932.
Part of the story is told from Lias point of view & that part is particularly interesting. I certainly did not find it difficult to get into, confusing, or difficult to understand the eugenetics as other have mentioned. It was a fantastic & interesting read. A must read for all Picoult fans.