Respect the book of shadows and grimoires.
Those books are personal journals of the witches before us and the witches around us.
They are meant to be learned and taken into account. You do not have to believe everything in someone's book of shadows and grimoires. It is for you to decide to believe or not. But just because you don't agree or believe doesn't mean you can be disrespectful.
Also if a witch does not wish for you to see or touch their book of shadows or grimoires. Then respect their wishes.
It is a matter of trust and honor to see another's book.
So please respect their wishes.