Which Tolkien book contains the lecture later published as On Fairy-Stories?

Tree and Leaf contains J.R.R. Tolkien’s lecture later published as On Fairy-Stories.

Tolkien originally delivered “On Fairy-Stories” as the Andrew Lang lecture at the University of St Andrews in 1938. The essay discusses the nature and purposes of fairy stories, including fantasy, recovery, escape, and consolation. It became one of Tolkien’s most influential statements about imaginative literature.

The essay was published in the 1964 collection Tree and Leaf, alongside Tolkien’s short story “Leaf by Niggle.” A revised version appeared separately in 1975, in a volume titled The Monsters and the Critics and Other Essays. That later edition is distinct from the original Tree and Leaf publication.

The title can therefore be confused with The Monsters and the Critics, especially because the 1975 version is widely cited by scholars. Tree and Leaf is the specific book that first collected the essay in its 1964 form, while the later volume is a revised reprint.