They write books or read from a book or books they consider true. The books are true in the sense that they represent dreams dreamt by different people. These books are not the result of an objective viewpoint though they may promote the illusion of objectivity. Many belief systems do perpetrate such an illusion. They are thought to be the result of an objective viewpoint.
Leaders can direct groups of people into waking nightmares.
This can be accomplished in several ways. Limited ideas may be spread into hungry minds. The fears of a group of people might be played upon. Leaders can manipulate the imaginations of their followers by permeating them with the images of their beliefs personified. They are told what is real.