The ghosts of Wales present many well-defined features. It is even possible to classify them, after a fashion. Of course, as with all descriptions of phantoms, the vagueness inevitable in creatures of the imagination is here; but the ghosts of Welsh tradition are often so old, and have been handed down so cleanly through successive generations, that in our day they have almost acquired definite outlines, as in the case of images arising from the perceptions. Always bearing in mind the risk of being lost in the labyrinthine eccentricities of popular fancy, compared to which the Arsinoë of Herodotus was unperplexing, I venture to classify the inhabitants of the Welsh spirit-world thus: 1. Departed Mortals; 2. Goblin Animals; 3. Spectres of Natural Objects; 4. Grotesque Ghosts; 5. Familiar Spirits; 6. Death Omens.