The main Sarah story line is interesting and compelling but Sarah's Key could have been half of its length.  Julia's research into Sarah's story was also interesting but her family life was not.  Books with convenient little endings wrapped in a bow do not work for me. de Rosnay continually repeats the same sentiments and script.  Her writing became so tiresome about mid-way through that I struggled to finish the book.  I get it, she lives in Paris, but I don't need to hear the streets, addresses and neighborhoods repeated with every move of Julia's life. If I was the type of reader who could abandon a book, I would have with this one.