Sarah's Key, by Tatiana de Rosnay

I thought this book might be depressing, seeing as it's about a little Jewish girl who locks her brother in a cabinet to hide him from the Nazis when they come to round them up in Paris during the war. (She didn't know they wouldn't be back soon.) But instead, it's very readable and absorbing, although of course, the subject matter is dark. It alternates chapters between the story of the little girl, and going to the camp, and everything she goes through, and of an American ex-pat journalist living in modern day Paris with her husband and daughter. She is researching the story of the Vel' d'Hiv' roundup, which is when the little girl was taken, and finds herself linked to the child. It's a real page-turner, and I thoroughly enjoyed it.