The book identifies to what extent it is possible to speak of a democratization of knowledge in Renaissance Italy. It establishes the boundaries of the present investigation within the Aristotelian tradition, and outlines democratization as a process capable of assigning power to people. It deals with how the democratization of knowledge historically is invested equally in ideas from religion and philosophy, involving the same democratizers, moved by similar intentions, employing identical techniques of vulgarization and targeting equivalent communities of recipients.