David Mong "kind of" saw Terrence McNally's "Master Class" in the spring of 1994 at what was then the annual Gathering at Big Fork (Montana), a project similar to Sundance's yearly Playwrights' Lab with actors, directors and playwrights assembled for work-shop-ping various works-in-progress.

"I say `kind of' because it was a reading. I was there as an actor and they were doing four or five new plays, and I heard they were doing this new play about Maria Callas. Zoe Caldwell (who went on to perform in the Tony Award-winning production of the piece) was there and so was McNally."I didn't know what I was getting into. I didn't know that much about opera or Maria Callas. And I have to confess, while I was sitting there, I felt `Master Class' wouldn't have any kind of longevity. That gives you some sort of idea about my instincts," Mong said.

Largely due to the play's eventual popularity, it's taken Salt Lake Acting Company more than two years to acquire the regional performance rights. Mong is directing SLAC's regional premiere of the highly acclaimed drama, which will run Sept. 23-Nov. 1 in the company's Chapel Theatre.

As for Mong's own predictions in 1994 about the play's potential longevity - it formally premiered on March 1, 1995, in Philadelphia, then had a successful engagement at the Mark Taper Forum in Los Angeles before moving to Broadway, where it won the Tony Award as "best play" for 1995.

Fay Dunaway's equally successful touring production kept most regional theaters from obtaining rights until this season.

"Having worked on the play now," said Mong, "I've discovered that `Master Class' is definitely NOT just for opera aficionados. It says some remarkable things about what it is to be an artist and about the relationship between the performers, the creative artists and the audience.

"For that reason alone - and because Maria Callas had such an extraordinary life . . . this has been a real eye-opener for me," he said.

Callas, who died in 1977 at the age of 53 (although the accuracy of her birth date has long been questioned), had a fairly brief career.

"She was a mega superstar," Mong said. "She retired, essentially, in 1965. Although she talked about new projects, she would always find some way to get out of them. At one time she told her lover, Aristotle Onassis, that it wasn't her voice that was gone, it was her nerve."

Callas' stormy relationship with the Greek tycoon is brought into the production. In one scene, Callas reflects on `Medea' and talks about Jason leaving her for a rich, famous princess - alluding to the Onassis/Kennedy affair.

The premise for "Master Class" is based on the classes Callas taught at the Julliard School in 1971-72. McNally sat in on them and tapped into these experiences for his script.

The diva's students, said Mong, are like lambs to the slaughter.

"One of the students, a soprano named Sophie, sings only one note and Callas stops her. These poor students have no idea what they're walking into. They haven't got a clue when they walk into this room with Maria Callas," Mong said.

For the SLAC production, Mong has a cast of seasoned Utah performers.

Anne Cullimore Decker portrays Callas.

"She's very knowledgable about opera as an enthusiastic patron. She's visited the major opera houses of Europe," he said.

Decker's recent work includes directing "Sylvia" for SLAC and performances in "Three Tall Women" and SLAC's world premiere of "K-Mille."

The three students attending Maria Callas' class are Sophie, Sharon and Tony, played respectively by Carolyn Talboys-Klassen, Anne Stewart Mark and David Winmill.

Both Talboys-Klassen and Winmill have extensive vocal and opera experience, including work with the Utah Opera Company.

While Mark is well-known to local theatergoers through her appearances in such productions as "Nine" at SLAC and several comedies and musicals for Pioneer Theatre Company, she, too, has an opera background, including performances in "Tales of Hoffman" and "Cosi Fan Tutte" at the University of Utah.

Another pivotal character in "Master Class" is Vinnie Wein-stock, the accompanist.

"It was tough to find a pianist who could commit to the 10-week rehearsal/performance period and someone who was comfortable acting on stage," Mong said.

He found Julliard graduate Steve Oldroyd, who also has extensive credentials as both a soloist and a vocalists' accompanist.

During the course of the two acts, audiences will hear two complete arias. During Decker's two "memory" speeches there will also be bits of the opera singer's recordings.

Mong noted that both he and his ensemble are wading into new artistic territory. Decker and Mark are stepping into the world of opera, while Talboys-Klassen and Winmill are entering the world of theater, which has a very different style of acting from opera.

Also in the cast is Tom Vick, as the Stagehand.

Mong was quick to note how much he has appreciated the assistance of opera coach/consultant Douglas Kinney-Frost, who is chorus master and assistant conductor for the Utah Opera Chorus.

"When you see how the music has to interface with the action and all of the technical issues involved . . . thank goodness we had Doug," Mong said.

Also working on the production are Keven Myhre, scenery and costumes; Jim Craig, lighting; and David Evanoff, sound design.

PERFORMANCES, ETC: Discounted previews will be 7:30 p.m. Wednesday and Thursday, Sept. 23 and 24, and 8 p.m. Friday, Sept. 25. The official opening night is Saturday, Sept. 26, after which it will continue on Thursdays at 7:30 p.m., Fridays and Saturdays at 8 p.m. and Sundays at 2 and 7 p.m. through Nov. 1.

Tickets for the previews are $12.50 and $16.50. Regular prices are $16.50 and $22.50, all available through ArtTix outlets or by calling 355-2787. There is also a "student rush" discount of $10.50 available at the door only for any seats remaining 30 minutes before curtain. ArtTix outlets are at the Capitol Theatre and selected Albertsons stores.