For library books (shared by all) scribbling, handwritten marginalia and comments are considered a form of damage and mutilation. You may be charged replacement costs for books in which you make pencil, pen, or highlighting marks.
If you are going to check a book out and see such marks, inform the staff at Circulation that the book already has such damage.
Take notes on a separate piece of paper or if possible on your laptop.
Taking Notes Separately
Highlighting in library books is very damaging, a source of distraction, and may result in the book having to be replaced. In addition, highlighted text tends to bleed through the page and obscure text on the other side.