The addition of a glossary is the only significant 'alteration' [='change, modification'] to the book.
They did a good job on the dress 'alteration'.
He made 'alterations' in/to his will.
(..) If she had a guy, I'd have known, believe me. - Sewing was her life. - Did you two ever work together? Sure. Me and Pam Malavesi used to help her do alterations for old Mrs Lippman. Can you give me Mrs Lippman's address? I need to talk to her. CALUMET CITY, IL So powerful. So beautiful. Precious? (..)1991 The Silence of the Lambs