I came across a review of this book on one of the blogs I read, but I can't remember which one. Anyhow I'm so glad I did because otherwise I'd never have known about it and it is real gem.
It tells the tale of two women living in Manhattan, New York - Olive and Amanda. Olive lives in 1907 and Amanda in 2007, the places they visit intertwine as their lives twist and turn. Even better are the turn of the century illustrations to help you envisage Manhattan 107 years ago. I have to admit I hit the google image button a few times too.
It has social history and relationships all mixed up and was an absolute delight to read.
I loved this book and read it all too quickly.