The "O'Farrell Pocket Companion for the Irish or Union Pipes" (OVPC) is a four-volume collection published in London in 1805-1810. It is one of the earliest known collections of specifically Irish tunes, though a good number are actually of Scottish origin. The transcription was done by Bill Black, who lives on Cape Cod, Massachusetts.

The *.txt files are the plain-text versions of Bill's *.doc files, to make them readable by people who don't have Microsoft's Word program. The T directory contain single-tune files named for the tune. The X directory used to contain the same files, named for the tune's number, but these have been deleted. The reel, jig, etc. directories contain tunes in that rhythm.