As someone else said on the New York Times post, I wish I could unread it! I hated it - there was nothing but ugliness in it and in this world, the reality is that periodically we "do" experience joy and happiness. While the author is very compelling, she obviously has experience with mental illness and possibly disturbed in some way herself. I've had mentally ill people close to me when I was young and this book clearly expresses the sickness in the nanny's mind. It also seems to be coming from someone who is not sympathetic or loving to the children at all, as well as the mother and father.
I wouldn't recommend reading this book as it's truly so sad and depressing. There was nothing gained by getting inside this nanny's mind since we all know that horrific things happen and people are disturbed but surely don't want to re-live it. I really didn't like reading this book that I had thought would be a great suspenseful thriller! - not! Just awful. ugh.