Fine; a book without significant defects and showing no signs of use beyond the lack of crispness or freshness present in a new book.
Very good; a book which shows some minor defects, but limited to those consistent with careful previous use. The defects should be minimal & insignificant.
Good; a bookthat clearly shows it has been used, but not abused, without having any serious defects caused by misuse, accidental or otherwise.
Fair; a book that is has serious defects, but retains the complete text and any plates or maps.
Poor; a book whose sole virtue is having retained the complete text in a readable form. It may be missing plates or maps; be heavily worn, soiled, etc.