Traditional music is rife with supernatural stories and references. Subject of worldwide belief, legend and testimony, fairies figure ubiquitously in Anglo-Celtic songs and tunes. No fewer than 11 of the Child ballads mention them. A number of pipe airs and fiddle pieces are said to have been learned from fairyfolk. In the magnificently engaging The Otherworld -- a trade-paperback book with two accompanying discs of field recordings -- the interaction of music and the supernatural in Irish rural life gets full due and thrilling exposure.

I have harbored a long interest in both folk music and the elfin tradition, and I wrote about the latter in my book on modern legends of fantastic places, Hidden Realms (2010), in a chapter titled "The Road to Fair Elfland: Fairies Experienced." Anyone who knows the relevant literature, richly documented by scholars and collectors over the centuries, will be struck, perhaps shocked, at how many fairy narratives purport to be from firsthand experience, as related by apparently sane and sincere persons. Explaining why this is so -- if it can be explained -- short of believing in fairies (problematic in itself, of course) can be a vexing enterprise.

Folklorists Lizanne Henderson and Edward J. Cowan, authors of the excellent Scottish Fairy Belief (2001), put it best: "It should be possible to believe one's informants without believing their explanations." I have coined the term "experience anomalies" to characterize such liminal phenomena: vivid perceptions of extraordinary entities encountered in some indefinable realm between the imagined and the "real." Such things are preserved in memory and testimony but by their nature are to be found nowhere else.

The Otherworld contains some colorful examples. One is from the Donegal fiddler Neillidh Boyle (1889-1961), a friend of the celebrated piper and folksong collector Seamus Ennis. Boyle matter-of-factly asserted that he had learned fairy music one night after being taken to a fairy wedding. "They played such wonderful embellishments," he recalled. "They said it was the enchanted music of Ireland that was long ago buried ... since the days of the old bards, and the days of the old pipers. ... I've practiced since a lot of their styles." To every indication Boyle was entirely serious.

Larger questions about the cause of supernatural experience aside, the two discs, compiled from recordings made by the Irish Folklore Commission (with many of the singers and players still alive, underscoring the continuing vitality of the native music), transcend simple ethnomusicological interest. These are sparkling performances that afford considerable pleasure and occasion delighted surprise. I know a fair amount about old ballads, but the opening cut on the first disc -- what amounts to a sequel to the more famous "Down by the Greenwood Side-ee-o" (aka "Cruel Mother") -- was entirely new to me. It's sung brilliantly by Mickey Connors, who was recorded at a Travelers' camp in County Carlow in 1972.

The book itself boasts an endlessly informative text and many resonant photographs of singers, musicians, collectors and -- most of all -- landscape features. The last of these record Ireland's unsettling countryside, home to fairies, banshees and ghosts, and serve to set already evocative songs and tunes in places that are of, at once, this world and the otherworld. If there is another compilation like this one, I have never heard of it, and I doubt that it could be as stimulating as this one, a unique and (almost literally) haunting excursion into mystery and melody.