Playing it, you're on your own - no idea, myself.

Using it? Sure, why not? The Dubliners, Clancy Bro.s and more used 'em over time. Heck, use a Theramin if you want in any case - it's your music you plan on making.

The 4 string or "tenor" banjo was very common in irish music for several years. It's sort of fallen out of vogue among recording artists, but people like Joe Bethancourt (<a href="www.whitetreeaz.com">www.whitetreeaz.com</a>) and Dave Cory ("www.myspace.com/thedavecoryband") are bringing it back into recording usage. Many of the sessions I have attended in recent years both in the U.S. and Europe have had at least one tenor banjo player.

So the short answer is "Yes, it id a 'celtic' instrument" in much the same way that the violin/fiddle (italian), guitar (spanish), concertina (English), bouzouki (Greek), tinwhistle (English) are "celtic".

As to how to play it? Pretty much the same as any other instrument, get yourself a tenor banjo, and find a teacher or instruction manual for the Tenor Banjo. Mel Bay produces an instruction manual specifically for the Irish Tenor Banjo beginner.

But I'd say start at the beginning, try going to "www.irish-banjo.com", which talks about different styles of banjo, where to get them, and even some beginners lessons on how to play them, and seeing what can be learned there.

Best of luck...

John Carty plays a mean tenor banjo, which is tuned like a fiddle but an octave lower. You can hear samples of some of his stuff here:
www.emusic.com/artist/105...563961.html