I think this would be a convenient feature for someone who likes to read lots of books. I recently found all of Jules Verne’s books on wikisource. A feature like this would make it easier to keep everything nicely organised.
I realise that this might not be feasible from a technical standpoint or not really a priority. It is something that I have been meaning to bring up for quite a while now, only now did I finally got around to actually do it.