Probably the best answer to this question is the "talking book." Equiano's slave narrative presents an early and powerful treatment of the power of literacy, a power that most slaves did not have and that they could only understand with a sense of awe and magic.

I had often seen my master and Dick employed in reading; and I had a great curiosity to talk to the books, as I thought they did; and so to learn how all things had a beginning: for that purpose I have often taken up a book, and have talked to it, and then put my ears to it, when alone, in hopes it would answer me; and I have been very much concerned when I found it remained silent.

Equiano did not invent this extended metaphor, as explained in the link provided below, but his is probably the best known formulation of the slave's view of the power of literacy.