Sometime in the late 1990s, when I was getting ready for a flight to Ireland with my father, I was startled to spot a familiar face among the crowd of waiting passengers. I pointed him out to Dad, who had no idea who he was. "That's Martin Hayes," I whispered. "He's an Irish fiddler. I have some of his CDs." I remember thinking for a moment before I could remember his partner's name. "He usually performs with Dennis Cahill," I added. "I'll loan you some of their music when we get home."

No, I didn't end up sitting beside Hayes on the plane, nor do I even recall if I saw him again on the flight or while disembarking at Shannon Airport. But it was cool nonetheless.

I mention this for no reason other than to say it was also cool to pick up a copy of Irish ethnomusicologist Gearoid O hAllmhurain's A Pocket History of Irish Traditional Music and again recognize Hayes -- who, like O hAllmhurain, hails from County Clare -- on the cover.

It's also a very good book. For its size -- as its name suggests, it's pocket-sized, and spans fewer than 160 pages -- it's surprisingly comprehensive. Even so, it's a difficult topic to cover thoroughly, no matter how many pages are at your disposal. As O hAllmhurain explains in his introduction:

There is no iron-clad definition of Irish traditional music. It is best understood as a broad-based system which accommodates a complex process of musical convergence, coalescence and innovation over time. It involves different types of singing, dancing and instrumental music developed by Irish people at home and abroad over the course of several centuries....

Although some musicians and singers are folk composers in their own right, not all new compositions are accepted as part of the living tradition. When they are, the original composer is often forgotten and the tune absorbs the influence of different dialects, instruments and musicians. Hence, the multiplicity of versions of well-known tunes and songs which is commonplace in Irish music. Within the bounds of the established tradition, experienced performers use improvisation in their interpretation of tunes, songs and dances.

He further breaks down the common types of songs and dance tunes, and notes that even further divergence occurs when you look at regional variation, such as the Sligo, Clare or Donegal styles. He discusses common instruments that fall within the tradition, mentions commonly misused terms (such as "Celtic music") which have little beyond marketing value, tosses out some of the basic themes in Irish songs, and lists some of the influential performers who have guided the evolution of the tradition over the years.

And we're still in the introduction!

The chapters that follow delve into periods of Irish history, beginning with "Music in Early and Medieval Ireland," "Tudor and Stuart Ireland" and "Jacobites, Dancing Masters and the Penal Era." There's "Music of the Exiles 1700-1830," "Pipers, Spallpins and Patriots: Pre-Famine Ireland," "Silence in the Land of Song: Post-Famine Ireland" and "Quebec to the Klondike: The Famine Diaspora." Moving into the more modern era, O hAllmhurain devotes further chapters to "Records, Radios and Halls: 'The New Century'," "Ennis, O Riada and the Fleadh: A Tradition Restored," and "From Friels' Kitchen to the New Millennium." He closes the book with some useful, more practical appendices: "Glossary of Traditional Music Terms," "Music, Song and Dance Collections," "Traditional Music Organisations," "Select Discography" and "A Note on Session Etiquette." (The final section, just a single page in a tiny font, is of particular use to tourists who don't understand the unwritten rules of attending a session in one of Ireland's many pubs, whether as a spectator or would-be participant. I wish every American visiting Ireland would read this page before they get on the plane!)

A Pocket History of Irish Traditional Music is a dense book, packed with a lot of information. O hAllmhurain writes in an academic tone that is concise, perhaps a bit dry at times, but never tedious. Given the date of publication, you will understand if some detail of the modern Irish music movement is missing; O hAllmhurain writes up until the appearance and impact of Riverdance and Lord of the Dance on the global scene, touching on the renaissance of the music in certain circles as well as its inevitable dilution as it becomes a marketing tool.

He leaves readers to draw their own conclusions. As it stands, this is an invaluable resource for anyone interested in the history of Irish music. It would, I think, be fascinating to see this book update to account for the tradition's further evolution over the first quarter of the 21st century.