Art Nouveau Piece...

This morning I was cleaning the living room and I dusted this piece Michael has that was his Grandmother's. I decided to take pictures of it as I would love to know more about it. I love the piece. It is Art Nouveau. It looks as though it once had color some spots. I am assuming it is to hold books? That is what we use it for but I am not really sure that is what it was intended. I have been nervous to take a more potent cleaner to it for fear it will take that last bit of paint off or ruin th piece. It doesn't have the name of the maker on it only a number on the inside of each end. It is adjustable - slides out to give more room. I am just curious to know more information about it but I am not sure I know where to start to find that kind of information.