Which Tolkien essay explores the meaning and purpose of fantasy stories?

On Fairy-Stories is Tolkien’s essay about the meaning and purpose of fantasy stories.

Tolkien first delivered the work as the Andrew Lang lecture at the University of St Andrews in 1938. The essay examines what Tolkien called fairy-stories, including their relationship to fantasy, imagination, recovery, escape, and consolation. He argued that such stories are not merely for children and can provide serious artistic and emotional value.

The essay was published in expanded form in 1947 and later appeared in collections including Tree and Leaf. Tolkien’s discussion of “sub-creation” describes how an author constructs a secondary world with its own consistency. On Fairy-Stories is often paired with Tolkien’s fiction because it explains principles visible in The Hobbit and The Lord of the Rings, but it is a critical essay rather than a novel.