I am saving pdf files into iBooks and I see that there is a category button at the bottom of the page, when viewing the pdfs in list form rather than bookshelf form. I see all my pdf's are in the category "uncategorized" and would like to assign them to categories. How can I do this? While on the subject, I see an author option at the bottom, next to the category option.... is there any way to specify an author for the pdfs? I will mention that I use dropbox to transfer pdfs so I'd prefer to be able to do these tasks directly on the iPad or, if I absolutely must, from the dropbox folder on a PC, with that being less desirable.