Tree and Leaf by J R R Tolkien

Tree and Leaf is a small book published in 1964, containing two works by J. R. R. Tolkien: a revised version of an essay called "On Fairy-Stories" (originally published in 1947 in Essays Presented to Charles Williams) an allegorical short story called "Leaf by Niggle" (originally published in the Dublin Review in 1945). The book was originally illustrated by Pauline Baynes. Mythopoeia was added to the 1988 edition.