Mark Twain tells in his "Connecticut Yankee" how his hero was able to overcome the wizard Merlin, because he knew in advance of an eclipse of the sun. And this was fiction, of course; but if you prefer fact, you may read in the memoirs of Houdin, the French conjurer, how he was able to bring the Arab tribes into subjection to the French government by depriving the great chieftains of their strength. He gathered them into a theatre, and invited their mighty men upon the stage, and there was an iron weight, and they were able to lift it when Houdin permitted, and not to lift it when he forbade. These noble barbarians had never heard of the electro-magnet, and could not conceive of a force that could operate through a solid wooden floor beneath their feet. Such things, trivial as they are, serve to illustrate the difference between ignorance and knowledge, and the power which knowledge gives. The man who knows is godlike to those who do not know; he may enslave them, he may do what he pleases with their lives, and they are powerless to help themselves. Anyone who would help them must begin by giving them knowledge, real knowledge. There is no such thing as freedom without knowledge, and it must be the best knowledge, it must be new knowledge; he who goes against new knowledge armed with old knowledge is like the Chinese who went out to meet machine-guns with bows and arrows, and with umbrellas over their heads. Once upon a time knowledge was the prerogative of kings and priests and ruling castes; but this supreme power has been wrested from them, and this is the greatest step in human progress so far taken. "Seek and ye shall find," is the law concerning knowledge today. "Knock, and it shall be opened unto you." In this, my Book of the Mind, I say to you that knowledge is your priceless birthright, and that you should repudiate all men and all institutions and all creeds and all formulas which seek to keep this heritage from you. Beware of men who bid you believe something because it is told you, or because your fathers believed it, or because it is written in some ancient book, or embodied in some ancient ceremonial. Break the chains of these venerable spells; and at the same time beware of the modern spells which have been contrived to replace them! Beware of party cries and shibboleths, the idols of the forum, as Plato called them, the prejudices which are set as snares for your feet. Beware of cant--that paraphernalia of noble sentiments, artificially manufactured by politicians and newspapers for the purpose of blinding you to their knaveries. Remember that you live in a world of class conflicts; at every moment of your life your mind is besieged by secret enemies, it is exposed to poison gas-clouds deliberately released by people who seek to make use of you for purposes which are theirs and not yours. In the fairy-tales we used to love, the hero was provided with magic protection against the perils of those times; but what hero