It is man who is, in contrast to fairies, supernatural (and often of diminutive stature); whereas they are natural, far more natural than he. Such is their doom.
…Fairy-stories are not in normal English usage stories about fairies or elves, but stories about …the realm or state in which fairies have their being. Faerie contains many things besides elves and fays, and besides dwarfs, witches, trolls, giants, or dragons: it holds the seas, the sun, the moon, the sky; and the earth, and all things that are in it: tree and bird, water and stone, wine and bread, and ourselves, mortal men, when we are enchanted.
…Most good “fairy-stories” are about the adventures of men in the Perilous Realm or upon its shadowy marches. Naturally so; for if elves are true, and really exist independently of our tales about them, then this also is certainly true: elves are not primarily concerned with us, nor we with them.
Happy birthday, Professor Tolkien! Quote taken from “On Fairy Stories.”