Before Microsoft Word, Google Docs, and Adobe Acrobat allowed us to track our edits, the publishing world used simple pen and paper. (Wild, right?!) Editors used proofreading marks to show what needed to change in formatting, punctuation, and more. Nowadays, some English programs teach their students to understand these marks so they can edit on paper correctly. Here’s a guide to help you learn them or — if you already know them — to help you reminisce.