Is the book listed as her the author, or her name, and then “together” with.
If someone wrote the book for her, using her words and ideas, they would be listed. If she wrote the books, using as we all do, an editor, then SHE indeed wrote the book and the Katie Couric and the rest should STFU about it.
It works and it provides a break from one for the other. I would say Lynn probably polished the final draft from cover to cover also and acted like an Editor in that final draft.