Thanks for all your helpful replies.
I wasted a bit of time yesterday trying to get the names of my books sorted out and getting them to appear in the order I want in the library. I have set up a filing system based on folders with letters for authors last names ('a' 'b' 'c' etc. in subfolders 'fiction' 'nonfiction' 'work'. So now the files display in the order I like with the 'sort by file path' option.
But the problem is even though I changed the names of the files to 'author - title.prc' only the pdf files actually display like that. Many of the others still display their silly original names like 'lizalambeth_maugham'. I believe I need to get the mobi2mobi application and edit the metadata within the prc file itself and that mobireader software is of no use either. I'm glad I have only got a few files to do.
I also downloaded the Webster dictionary from Fictionwise. It didn't work at first because I put it in its own folder rather than the ebooks folder. But it's OK now.