Tomas O'Canainn, an Engineering Professor at UC Cork and iellean piper/sean nos singer par excellance, succeeded Sean O'Riada as leader of the "Fili", a group dedicated to the traditional music of Ireland. He has at least one CD, ["Tomas O'Canainn: with pipe and song", Outlet Recording Co., Ltd, 15/21 Gordon St., Belfast BT1 2LG; Phone (01232)322826, FAX (01232)332671], and a book, which I think is titled "Irish Traditional Music" (I have it, someplace, but can't put my hands on it just now). I had the opportunity to meet him and get to know him a bit when he performed her on the CCE tour in '95. Dedicated fellow, and very nice man. He was 61 at the time, so he'd be 66 0r 67 at this point. As I recall from the book, the "signature" features of traditional Irish music are the fondness for modes and the frequency of 6th intervals in the melody line. "A Nation Once Again" is a good example of the fondness for 6ths. I heartily recommend him as a place to start if you want to dig into the scholalry side of Irish Traditional music. On the ancillary topic of "Celts", scholars who study the question still seem somewhat uncertain as to whether the "Celts" were a specific people who spread across europe, people who embraced a culture which spread across many peoples of europe in variant forms, or some combination of the two. I don't know that the question can ever be answered with any great certainty, but I tend to favor the combination approach. That makes the many "variations on a theme" that are popularly subsumed under the name "Celtic" easier to understand, though not necessarily any easier to define. Thanks for a most interesting question, Andres.