I've found the method to sort books in calibre by author's last name. However, what I really want to do is this: when I convert a book from azw to epub, instead of saving the author's name as "John Jones", save it as "Jones, John" or "Jones John". That way the book folders will also be named and sorted by author last name and when I use an e-reader, it will sort the books by LN/FN. I'm using Pocket Reader for android on my phone, so if I can convince PR to sort for me without having to do anything in calibre that would be awesome.