These are some "realia" of what the books series look like in my kids' library at their school. I'm going to take this idea to the library where I work and see if she would like to do the same kind of thing. Not all books in a series are written by the same person, and I think putting the series together like these on the shelf make it easier for the students (and me) to find them. It also helps keep the books in order so the students can see which book comes next in the series.