Have you ever been to an Irish pub or special gathering where a small circle of people pulled out their various instruments and just started playing, without pause, energetic and mythical sounding sets of tunes that just turn and turn into the night? The group may be as small as two people, or as large as a small orchestra, and while some people may be close friends, others are total strangers. What they all have in common are their memorization of dozens, sometimes hundreds of tunes, all shared in a common ancestry - not hereditary, but simply musical. If you play a stringed instrument and haven't been a part of what is most often called Irish session music, you absolutely must, and this St. Patrick's Day is a great opportunity. If you are hooked on Celtic fiddling, a tune book and some advice will help you in becoming one of that timeless circle of musicians.