Just found this cool book online, you can read it here: http://www.sacred-texts.com/neu/celt/ffcc/ Here's a description of it from the site: This is one of the most in-depth and scholarly attempts to explain the phenomena of the Celtic belief in fairies. Based on Evans-Wentz' Oxford doctoral thesis, it includes an extensive survey of the literature from many different perspectives, including folk-lore, history, anthropology and psychology. The heart of the book is the ethnographic fieldwork conducted by Evans-Wentz, an invaluable snapshot of the fairy belief system taken just on the cusp of modernity. There are regional surveys of the fairy-faith in Ireland, Wales, Scotland, Brittany and the Isle of Man. Evan-Wentz later went on to become one of the leading authorities on Buddhism, and published many of the key documents of Tibetan Buddhism including the Tibetan Book of the Dead. Evans-Wentz examines each of the hypothetical explanations of the fairy phenomena. Among these are the theories that fairies were a reclusive race of dwarfs, that they are disembodied spirits, or that they are a figment of our imaginations. Evans-Wentz concludes that they may indeed be a manifestation of inhabitants of a higher reality that only some of us are able to view, let alone understand. We come away from this study with a multi-dimensional view of the fairies, who, much like the grey aliens of UFO belief, inhabit a narrative which seems too consistent to be the product of insanity, yet too bizarre for conventional explanation.