What was the title of J.R.R. Tolkien’s 1931 essay about the nature and purpose of fairy stories?

J.R.R. Tolkien’s 1931 essay about fairy stories is titled On Fairy-Stories.

Tolkien first delivered the work as the Andrew Lang Lecture at the University of St Andrews in 1938, although the essay’s ideas developed from his earlier academic thinking. It was later published in expanded form in the 1947 collection Essays Presented to Charles Williams and became one of his most influential statements about fantasy.

In the essay, Tolkien argues that fairy stories are not merely children’s entertainment. He discusses the nature of the fairy-story, the functions of fantasy, recovery, escape, and consolation, and the value of what he calls the eucatastrophe: a sudden joyful turn in a story.

Readers often connect the essay’s theory to The Lord of the Rings, especially its treatment of hope and providence. However, On Fairy-Stories is a work of literary criticism and theory, not a fictional tale set in Middle-earth.