What was the name of J.R.R. Tolkien’s first published scholarly essay on fairy stories?

J.R.R. Tolkien’s influential essay on fairy stories is titled On Fairy-Stories.

Tolkien developed the essay from the Andrew Lang lecture he delivered at the University of St Andrews in 1938. A revised version was published in 1947, and it later appeared in collections of Tolkien’s nonfiction. The essay explains Tolkien’s ideas about the nature, purpose, and power of fairy stories.

It is especially known for Tolkien’s discussion of fantasy, recovery, escape, and consolation. He also introduced the concept of the “secondary world,” a coherent imagined world created through a story’s internal rules. These ideas became important statements of Tolkien’s literary theory and help explain why he defended fantasy as serious art.

On Fairy-Stories is sometimes confused with Beowulf: The Monsters and the Critics, Tolkien’s famous 1936 lecture on Old English literature. Leaf by Niggle is a short story, while A Secret Vice concerns Tolkien’s interest in constructed languages.