Symbolism, Imagery, Allegory
Ah, the power of words. Like Belle in Beauty and the Beast, Miri finds utter magic in words once she's capable of reading:
Once words had been invisible to Miri, as unknown and uninteresting as the movements of a spider inside a rock wall. Now they appeared all around her, standing up, demanding notice—on the spines of books in the classroom, marking the barrels of food in the kitchen and storeroom, carved into a linder foundation stone… (5.1)
For Miri, reading isn't just something that she has to learn in order to become academy princess—it becomes a gateway to knowledge and learning. Through books, she's able to learn about places outside of Mount Eskel and to see what the world holds, and in this way, books provide a window into the endless possibilities that await Miri.
And one of these possibilities, of course, is becoming a teacher—which is exactly what Miri intends to do as our story ends. Now that she's able to read, Miri wants to empower other curious people to learn to do so as well, to help open the world up for more people who live in Mount Eskel. In this way, books also symbolize Miri's investment in community and her commitment to fairness. She believes education should be available to anyone who desires it, and is ready to make that her life's work.