Mr. Penumbra’s last name can refer to an area of partial shadow, or a shadowy, marginal area. How does this meaning relate to the novel’s main themes? What does it suggest about the role of the bookstore in the novel?

What were your initial theories about the bookstore’s mysterious customers and the books shelved on the Waybacklist? Did you have any idea what Manutius’s book would be about?

At the heart of the novel is the collision of old, manual technologies and new, digital ones. How do Clay and his friends build a bridge between these two worlds?