Jo

If Jo was a physical, tangible object she would definitely be a book. She would not be a book just because she works in a bookstore but because she is sort of closed to other people unless they put in the effort to get to know her. This describes a book because a person doesn't know what is in a book unless they put in the effort to read it. Jo is also very smart and full of knowledge, especially for her age. The people who just meet Jo don't always see the real Jo. She likes to trick them into thinking she is something she is not.  You can't judge a book by its cover with Jo like when she meets Charlotte she says her name is Josephine and lies about her parents. She does not tell her that her mother works at a brothel and she doesn't know who her father is. Also at the party at Charlottes uncles no one there knows about her family's past so she makes everything up about herself. The only people who know the true Jo put in the effort to get to know her.