" The Emerald City, the Yellow Brick Road, magical slippers, a brave farm-girl protagonist, and, of course, the good and bad witches are all now seemingly timeless icons from what some have called “the first American fairy tale.” But several of these ideas were not invented by Baum out of whole cloth. In fact, a great many of them can be traced to the influence of his mother-in-law, the suffragist and equal rights pioneer Matilda Joslyn Gage. "

― Pam Grossman , Waking the Witch: Reflections on Women, Magic, and Power