J.R.R. Tolkien's On Fairy-stories is his most-studied and most-quoted essay, an exemplary personal statement of his own views on the role of imagination in literature, and an intellectual tour de force vital for understanding Tolkien's achievement in writing The Lord of the Rings.Contained within is an introduction to Tolkien's original 1939 lecture and the history of the writing of On Fairy-stories, with previously unseen material. Here, at last, Flieger and Anderson reveal the extraordinary genesis of this seminal work and discuss how the conclusions that Tolkien reached during the composition of the essay would shape his writing for the rest of his life.