There are two ways that books are being saved in the novel. The first is that people are hiding them in their houses, which is the less effective of the ways. Most of the book is about the consequences of being caught with books in your house. The second way isn't introduced until the end of the novel, but is key in understanding the themes of the novel. Montag joins a group of renegades, most of whom are artists, professors, or philosophers. They have been memorizing the texts of classics books, each taking responsibility for remembering different pieces of literature. They know that a time will come when society will need the words and philosophies from these books, and are preserving them in their minds for that day.