In a briefcase under a pile of binders and papers I found a page of notes taken on February 24, 2006. It started with a quote of something profound that Michael Mullen said.
Play the tunes you know. ―Michael MullenAfter the quote was list with the heading Tunes I Know. It consisted of 19 tunes that I can play/lead pretty much at the drop of a hat.
Interpretation In order to get better at playing traditional Irish music one must learn tunes and develop your skills. Michael recommends playing the tunes that you know and work on your skills and new ornamentation within that context.
I have spent over 20 years in the study of Danzan Ryu Jujitsu and in all that time there some techniques that has been used in practically every workout that I have never done exactly the same way twice. With deeper understanding comes a deeper insight.
Use these books if you want to build your tune foundation but it isn't about how many tunes you "know" but how much you enjoy playing them and playing them well.