Before MacKenzie Scott signed the Giving Pledge and started on her path to give away her $36 billion net worth, she went looking for a paragraph in a book she’d marked up during her college years. Scott signed the Giving Pledge on May 25, 2019, just months after her divorce from Amazon founder Jeff Bezos left her with a roughly 4% stake in the company. But the billionaire philanthropist and author didn’t open her letter with talk of foundations …