Books can only be edited once you've added them to your collection. Think of books in the catalog as books in a store, you aren't able to personalize them until you've purchased a copy.
To edit your books, navigate to the My Collection page and use the Action Menu on the book you would like to update.
In the Edit My Book form, there will be several details that you can update.
The Edit My Book form let's you track signatures on multi-author titles.
If you're editing a special edition of a book (Goldsboro Brotherhood in this example). You'll notice that you add your number (My Number) and the signed toggle by Mike Chen's name is disabled, it's because the book came pre-signed from Goldsboro so you can't override this detail. You are able to change the signed status if you get personalization or inscription added to your copy of the book.