“It must be borne in mind that everything the propagandist does or says is for effect—most commonly the effect on fools. The public wants not truth but a show?”

As quoted in Cosmopolitan (December 1892).
Context: A so-called magician, more than a poet, must be born with a peculiar aptitude for the calling. He must first of all possess a mind of contrarieties, quick to grasp the possibilities of seemingly producing the most opposite effects from the most natural causes. He must be original and quick-witted, never to be taken unawares. He must possess, in no small degree, a knowledge of the exact sciences, and he must spend a lifetime in practice, for in the profession its emoluments come very slowly. All this is discouraging enough, but this is not all. The magician must expect the exposure of his tricks sooner or later, and see what it has required long months of study and time to perfect dissolved in an hour. The very best illusions of the best magicians of a few years ago are now the common property of traveling showmen at country fairs. I might instance the mirror illusions of Houdin; the cabinet trick of the Davenport Brothers, and the second sight of Heller — all the baffling puzzles of the days in which the respective magicians mentioned lived. All this is not a pleasant prospective picture for the aspirant for the honors of the magician.

Counterterrorism and Cybersecurity: Total Information Awareness (2nd Edition), 2015

Posthumous Pieces (1968)

Actually from "War Propaganda", in volume 1, chapter 6 of Mein Kampf (1925), by Adolf Hitler
Misattributed

Source: Love in Action: Writings on Nonviolent Social Change

quoted by Gary Wolf in "The Curse of Xanadu" http://www.wired.com/wired/archive/3.06/xanadu_pr.html in Wired (6/1995)

Source: The Way of Kings

Source: Freedom, Loyalty, Dissent (1954), p. 15

Source: Academy Series - Priscilla "Hutch" Hutchins, Odyssey (2006), Chapter 10 (p. 85)