thanks for the information, katu.
I now understand how to change the root folder, but I not sure about favorite folders. I did enable favorites in the settings; but I don't see a "system" folder in my database folder.
Also, in my experiments, I noticed if I create a new folder category for my books, say, for example, "novels," and move a book into it, when I begin using my eReader again, the book appears as "new" and all bookmark information is lost. Is it advisable not to change a book's folder once you have begun reading it, or is there a way to link the book back to its bookmarks?