 Breathnach started work as a civil servant with the Department of Agriculture, but in 1965 switched to the Department of Education where he was responsible for collecting music from around Ireland.In the 1950s he decided to publish some of his music collection.Tunes were contributed by pipers such as his uncle Joe, John Potts, Tommy Reck, Matt Kiernan and Willie Clancy, fiddlers such as John Kelly, Donncha Ó Cróinín, Tommy Potts and Tom Mulligan, flutists and whistlers such as John Egan, John Brennan and Michael Tubridy, and box-player Sonny Brogan.