From the Commonplace Book: Tolkien on Reading Difficult Books

"Life is rather above the measure of us all (save for a very few perhaps). We all need literature that is above our measure--though we may not have sufficient energy for it all the time. But the energy of youth is usually greater. Youth needs then less than adulthood or Age what is down to its (supposed) measure. But even in Age I think we only are really moved by what is at least in some point or aspect above us, above our measure, at any rate before we have read it and 'taken it in'. Therefore do not write down to children or to anybody. Not even in language. Though it would be a good thing if that great reverence which is due children took the form of eschewing the tired and flabby cliches of adult life. But an honest word is an honest word, and its acquaintance can only be made by meeting it in a right context. A good vocabulary is not acquired by reading books written according to some notion of the vocabulary of one's age-group. It comes from reading books above one."  J.R.R. Tolkien, letter, April 1959