"Christmas Revels," one of Boston's most beloved holiday traditions, returns for its 39th season on December 11.  Celebrating the winter solstice, "Revels" includes holiday carols, dancing, storytelling, folk songs, and the production's signature piece, "Lord of the Dance," which ends with the audience dancing in unison out into the lobby of the theater. (For those few among the uninitiated, the hallmark of "Revels" is audience participation.)

Revels was created by the late musician and educator John Langstaff, who presented the first "Christmas Revels" at Sanders Theatre in 1971.  Each year, the show is set in a new geographic location.

Paddy Swanson, the Revels' Artistic Director, has been with the group for 20 years. With more than three decades of experience both here and abroad, Swanson has taught at the London Academy of Dramatic Art, the London Drama Centre, and New York University. He has also served as Artistic Director of the Castle Hill Festival in Ipswich.

We recently spoke about this year's production as well as his own interesting beginnings. Following is an edited portion of our conversation.

BIR:  I understand you were born south of Boston and that you have both Irish and American citizenship. Tell me about that.

PS:  My mother actually came over (from England) to see the 1939 World's Fair with her cousin.  Our family is Irish going back through my mother - my grandparents are both Irish, from the west of Ireland in County Mayo.  So she came over with a cousin of hers. I think they were young characters looking to see the relatives in the states, the Burkes.  And then the war broke out and she was stuck here because the lanes were closed. And so she lived with my Irish family over here and met a guy in the Army Air Force and married.  And he died.  And at the end of the war, she went back to England with me, a one year old, and I was brought up in Manchester.

BIR: And the dual citizenship?

PS:  I think I had the choice of citizenship when I was 16 or 17  and I opted for keeping my American passport.  At some point, one of my relatives said, 'Well you know, because your grandparents are both Irish, if you have the original documents, you can apply for Irish citizenship.' So I did, and there you are.

BIR:  So Revels will be opening shortly.  Tell me about the show's setting this year.

PS:  Sometimes people think of what we do here as 'playing at home' or 'playing away,' in sports terms.  Occasionally we'll go very far away, the Balkans or somewhere . . . It's very exciting, but sort of foreign.  What people think of as home territory is either the kind of English medieval thing Jack started, or America, and this year is going to be America.

BIR: That must provide a broad brushstroke of musical choices.

PS:  America has such an enormous amount of influences, musically and culturally.  So we're taking just a few things, some fairly close to home like the Shape-note music that was popular around New England, which is wonderful stuff.  Sort of strong harmonic pieces and very distinctly American.  And the Shakers, who have their own culture. Very beautiful melodies, very simple. But we're setting it in Appalachia. So what people will see when they come into the theater is a sort of reproduction of an Appalachian Mountain village.

BIR:  I know you have an 80-member ensemble including The Pinewoods Morris Men, The Cambridge Symphonic Brass Ensemble, and David Coffin - for his 30th year.  Who else is part of this year's show?

PS:  Suzannah Park, a young woman who splits her time between Chicago and Southern Appalachia and really embodies [Appalachian] music. She has a wonderful ear and voice.  Then we have a Native American who will be coming from Colorado . . . Leon Littlebird. He's a flute maker and has a wonderful performance sense.  And then African American; we'll be using some of the Christmas ceremonies, like the Jonkonnu, which is common to all of the Caribbean and New Orleans and South Carolina. [It has] a sort of mummers' like tradition where they visit houses and perform these kind of hypnotic dances in disguise.  And they use junk band music, which is made up of pots and pans and so on . . .  it's spiritualism and also gospel.  So we've got a good array of styles.

BIR: Audiences have so many entertainment choices during the holidays. What is it that has made Revels such a longtime favorite?

PS:  That's an interesting one. I think it's because there is a kind of hunger for tradition, things that have been passed down over the years.  Even within Revels there are traditions. They're what we call touchstones . . . There are always new things, but for instance, at the end of the first act, you can guarantee that will be 'Lord of the Dance,'  just before the intermission.  People look forward to that, and if you took it out, there would be problems, as there were when Jack decided that the last piece - the Sussex Mummers Carol that we do at the end of the show - -wasn't appropriate for whatever show it was they were doing that year - maybe Russian. He replaced it with something else.  And the audience, after they had sung whatever was there, they literally didn't leave.  They stood up and sang Sussex Mummers Carol,  which indicated very clearly to us that this is larger than whatever we wanted to do.  This was, in a sense, a community that was already there saying 'this is ours.'

BIR: With Sanders Theatre at Harvard having been inspired by Christopher Wren's Sheldonian Theatre at Oxford, England, it's an ideal home for a production that holds tradition and ceremony in such high regard.

PS:  The sense of place . . . helps in some way.  'Revels' is a kind of secular celebration of Christmas and Sanders Theatre is a kind of secular church.  It's not a religious place, but I think it does help to bring out that sense of ritual.

"The Christmas Revels: In Celebration of the Winter Solstice," December 11 - 27, Sanders Theatre in Harvard University's Memorial Hall, 45 Quincy Street in Cambridge.  617-496-2222.