Let us not divide the human race into Eloi and Morlocks: pretty children --"elves" as the eighteenth century often idiotically called them -- with their fairy-tales (carefully pruned), and dark Morlocks tending their machines. If fairy-story as a kind is worth reading at all it is worthy to be written for and read by adults. They will, of course, put more in and get more out than children can. Then, as a branch of genuine art, children may hope to get fairy-stories fit for them to read and yet within their measure; as they may hope to get suitable introductions to poetry, history, and the sciences. Though it may be better for them to read some things, especially fairy-stories, that are beyond their measure rather than short of it. Their books like their clothes should allow for growth, and their books at any rate should encourage it.
J.R.R. Tolkien from his essay "On Fairy-Stories".