Jack Viertel, artistic director of City Center Encores!, is trying to explain the special alchemy that repeatedly occurs between performers and audiences during the celebrated concert series devoted to shows from musical theatre's illustrious past. "It's almost like magic," says Viertel. "The music somehow reaches right past your intellectual faculties and sticks its finger on some kind of joy buzzer inside your brain that isn't driven by logic. That is the way the best American musicals have always worked. If you deliver 'Sing for Your Supper' with Sarah Uriarte Berry, Debbie Gravitte and Rebecca Luker, people will go berserk. That's how the species reacts. It's a great song with a great arrangement, and they're great performers, but that number was so much more than the sum of its parts."

"Sing for Your Supper," from Rodgers and Hart's The Boys From Syracuse, was reprised by those three singers back in November, when Encores! kicked off its tenth anniversary season with a gala program featuring many goose-bump moments from its previous nine years. The 2002-2003 season began in February with Harold Arlen and Truman Capote's House of Flowers and concludes in May with Richard Rodgers and Samuel Taylor's No Strings. Encores! is currently presenting its first operetta, The New Moon by Sigmund Romberg, Oscar Hammerstein II, Frank Mandel and Laurence Schwab. "Operettas were a big part of American musical theatre history in the twenties," says music director Rob Fisher. "It seems important to acknowledge their contribution to the evolution of the form. We chose New Moon because it has a decent story and an unbelievably good score."

Judith E. Daykin, the outgoing president and executive director of City Center, conceived of Encores! when she arrived at the venerable theatre in 1992. Her idea was to present scaled-down productions of musicals with distinguished scores that were unlikely, for various reasons, to be staged again on Broadway. "We represent the golden age of an indigenous American art form," says Daykin. "Irving Berlin, Rodgers and Hammerstein, Rodgers and Hart, George and Ira Gershwin, and Cole Porter are part of our very proud past. Somebody needs to pay attention to that past."

Attention is indeed being paid. Encores! offers five performances of each of three musicals every year, and virtually every show has been rapturously received by critics and audiences. In fact, Encores! has become such a vital part of the theatre scene in New York that it's hard to imagine there was ever any doubt the venture would succeed. But after the first season (Fiorello!, Allegro, Lady in the Dark), which lost a lot of money despite good reviews, no one was certain that Encores! had much of a future. "I remember the advisory committee meeting after the first season," says Viertel, "when we talked about what to do the next season. And somebody said, 'The second season is only about one thing: it's about having a third season. You're going to have to do something that audiences really want to see, or we'll be out of business.'"

That something was Berlin's Call Me Madam with Tyne Daly, which inaugurated the second season. "She turned the corner for us," says Daykin. "That first year, it was very difficult for Jay Binder, our invaluable casting director, to get people to participate in a limited number of performances for a tiny amount of money. When Tyne appeared in Call Me Madam, that made all the difference." Encores! is best known for resuscitating the reputation of an overlooked classic, Kander and Ebb's Chicago, which was presented at the end of the third season in 1996, and transferred to Broadway six months later. In the ensuing years, there have been rumors of various other Encores! productions moving on, but none has. "Those expectations are all external," says Fisher. "We're still picking the shows the way we always picked them: We never think about them having a life beyond those five performances."

The Encores! team has a master list of about 100 shows they hope to do, and after conferring with a "kitchen cabinet" of people, the selection ultimately comes down to a joint, personal decision by Viertel and Fisher. They try to present contrasting and diverse works each season, including one, says Viertel, that's a "big, loud party." The orchestrations and arrangements of every show are as close to the original as possible, and the focus on the music is underscored by the presence onstage of the terrific Coffee Club Orchestra and Fisher, whom Viertel calls "the soul of Encores! and the reason we exist."

"The scores of these older shows are written with a joy and exuberance that are so easily generated when we do them," says Fisher. "I don't see people creating things these days that have that effect. The material we do speaks for itself, and the level of appreciation from our audience is extraordinary."