Joseph Papp is on a roll.

It's not the first time the producer has been lucky. After all, a while back he took a chance on a hare-brained idea of a musical about a group of kids trying out for a musical -- and ended up with "A Chorus Line."

But in a season in which no one else stands on both theatrical legs for more than 30 seconds, Papp's achievements stand out like the Statue of Liberty.

"Papp's A Poppin'," says Variety.

"You never know," says the producer.

He is superstitious, see.

With no fewer than four hit plays currently residing in his Public Theater (424 Lafayette St.), surely the man who is to theater in this town what Edward Koch is to government or Donald Trump is to dynasties must know something.

"Well, it's a lot of work," he offers.

For instance: Last December Papp gave a play a sex change. "Coming of Age in SoHo," the first play in some time by Albert Innaurata, author of the hit comedy "Gemini," floundered badly in previews -- much hissing and booing and walkouts in the middle of scenes. After many rewrites and epic battles between producer and playwright, it was shut down for several weeks and recast. In place of the original lead, a woman who rediscovers the son she abandoned, Papp and Innaurata substituted a "homosexual who suffers from temporary amnesia in the company of strong women," who rediscovers his son. "The audience," Papp recalls, "found it easier to believe a gay man would abandon his son." "SoHo" has been extended through March 31 to meet the demand for this unusual play.

"I have to travel a lot," he says, offering another reason -- a good one now that much of New York's theater comes from points west and east.

Last year in London, Papp found two productions he wanted to bring to the States. One was "Tom and Viv," about the awful marriage of T.S. Eliot and Vivien Haigh-Wood. Despite mixed reviews, the play is sold out for the duration of the run, through March 10.

Last night Papp opened the other one, "Virginia," the Edna O'Brien play about the life of Virginia Woolf, particularly her friendship with Vita Sackville-West. A star-studded audience attended the premiere. Advance tickets have been selling almost as well as slices of pizza in the nearby East Village pizza-video galleries.

"Bloomsbury is popular," he says shyly, referring to the London neighborhood Woolf and Eliot and Sackville-West occupied.

Asked whether he thinks that serious issues are also popular and possibly the keys to his success, Papp laughs. Homosexuality and the Mafia in the case of "SoHo" were mentioned, misogyny in the case of "Tom & Viv," lesbianism in "Virginia."

"Don't forget Vietnam," he says slyly.

"Tracers," produced and directed by and starring the Vietnam Veterans Ensemble, sold out weeks in advance. Three major television networks intend to use clips from it to commemorate, on Friday, the 20th anniversary of the first major installment of American troops in Vietnam.

Asked whether he thinks that aggressive press relations had anything to do with his success, he laughs and says, "It never hurts, but it doesn't account by itself for the success.