To those who say that children must not be frightened and means to keep their minds from knowledge of the world around them:

Lewis, Clive S. The Chronicles of Narnia. New York: HarperCollins, 2004.

Page 776 - On Three Ways of Writing for Children

"There is something ludicrous in the idea of so educating a generation which is born to the Ogpu and the atomic bomb. Since it is so likely that they will meet cruel enemies, let them at least have heard of brave knights and heroic courage. Otherwise you are making their destiny not brighter but darker. Nor do most of us find that violence and bloodshed, in a story, produce any haunting dread in the minds of children. As far as that goes, I side impenitently with the human race against the modern reformer. Let there be wicked kings and beheadings, battles and dungeons, giants and dragons, and let villains be soundly killed at the end of the book. Nothing will persuade me that this causes an ordinary child any kind or degree of fear beyond what it wants, and needs, to feel. For, of course, it wants to be a little frightened."