Books

"True freedom comes from education, which is why so many rulers lock up books, ban, or burn them. Keeping them in the hands of the privileged and away from the masses. The key to tyranny and control is to keep someone ignorant. If they don't know anything different, they'll find comfort in what they know rather than fighting for something they could have." 

- Elowen Atarah Veles (from Olivia Rose Darling's Wrath of the Dragons)