Wikipedia has a fairly good summary, which would at least get you going on this.
Now, bear in mind that the following is taken directly from Wikipedia, as the article exists today, 2nd January 2019. So, it has whatever bias and perspective the various contributors may have put on it. If anyone takes issue with it, take it up with Wikipedia, not me.
Quote:
Most of Carolan's compositions were not published or even written down in his lifetime. They survived in the repertoires of fiddlers, pipers, and the last of the old Irish harper/singers. They were collected and published during the late 18th century and beyond, largely beginning with the work of Edward Bunting and his assistants in 1792.[7]
A small sampling of Carolan's music was published during his lifetime. One of the first such publications was in Neale's A Collection of the Most Celebrated Irish Tunes ..., Dublin, 1724.[8]
The definitive work containing all 214 of Carolan's tunes as identified by Donal O'Sullivan (1893–1973) is the 1958 edition (2001 reprint) of Carolan: The Life Times and Music of an Irish Harper.[9] Partial lyrics (and all known sources of lyrics) are mentioned in the text description of each piece, but are not matched to the written music. O'Sullivan does not include any of the handful of alleged Carolan songs that he considers to be erroneous, such as: "Dermott O'Doud", "Planxty Miss Burke", and "The Snowy-Breasted Pearl".[10]
A comprehensive edition of Carolan's Songs & Airs containing new arrangements for harp of all 214 airs, along with an additional 12 airs from the Appendix of the 2001 edition[11] was published by Caitríona Rowsome in 2011.[12] This book includes an instance of each of Carolan's undisputed surviving lyrics and metrically sets the lyrics note-for-note to the sheet music airs. Each of the 226 harp settings in this book are played by the author on a neo-Irish harp (book and 4-CD set). This is the first time that all of Carolan's lyrics have been set to the airs and has been welcomed as "a task that has needed doing for many years".[13] The 4-CD recording is of harp music without vocals, but the book includes the sheet music for interested singers. Some English translations are also attempted, despite the author not being a translation scholar.