J.R.R. Tolkien’s essay discussing “sub-creation” and “eucatastrophe” is titled On Fairy-Stories.
Tolkien developed the essay from a lecture delivered at the University of St Andrews in 1938. He argues that fairy stories should not be dismissed as simple children’s entertainment. In his account, fantasy can offer recovery from habitual ways of seeing, escape from oppressive limitations, and consolation through the shape of the story.
“Sub-creation” describes the writer’s creation of a coherent secondary world, while “eucatastrophe” means a sudden joyful turn in a story. Tolkien considered this positive reversal an important feature of fairy-story tradition. The essay was published in expanded form in 1947 and later appeared with the short story “Leaf by Niggle” in the volume Tree and Leaf. Although Tolkien uses examples from myth and folklore, On Fairy-Stories is an essay about the nature, value, and craft of imaginative literature, not a collection of fairy tales.