Back in 1974, before the mile-high platform shoes, polyester-blend leisure wear, frenzied international tours, and inevitable backlash, Abba were just another Swedish pop group trying to beat Olivia Newton-John in the Eurovision Song Contest. Even after a zesty number called " Waterloo " disposed of the competition and established Abba as pop superstars whose music would eventually outlive their indestructible poly-blend pants, co-founder Björn Ulvaeus could scarcely have imagined that a quarter-century later, he’d be co-producing Mamma Mia!, a rousing musical built around Abba’s songs (even the show’s title is taken from one of the group’s dozen-plus Top 40 hits).

" No, when we were writing, we thought they were pop songs — something for the day, possibly for the month or something like that. I never thought they’d last, " he says over the phone from the band’s home town, Stockholm. " When we split up [in 1982], I thought Abba would be completely forgotten. I was stupid. "

The musical, which premiered in London to sold-out houses in 1999 and has enjoyed similar success in Toronto, Chicago, San Francisco, and Los Angeles, comes to Boston’s Colonial Theatre for a limited engagement starting this Friday before making its Broadway debut in October. Directed by Phyllida Lloyd, a veteran of British theater and opera, it’s based on British playwright Catherine Johnson’s lighthearted story about family, freedom, and tradition — specifically the relationship between a single mother, Donna, and her soon-to-be-wed daughter, Sophie. And somehow it manages to weave 22 individual Abba tunes into a single narrative.

Despite encouragement from co-producer Judy Craymer (who had worked with Ulvaeus, his Abba songwriting partner Benny Andersson, and English lyricist Tim Rice on the ’80’s musical Chess), Ulvaeus himself was skeptical that the feat could, or should, be done — until he saw a performance of Grease with his wife (not Abba singer and one-time spouse Agnetha Fältskog, whom he divorced in 1979) and two daughters. " Suddenly, I could see what potential such a musical could have, because there’s so few out there that are happy, uplifting, and funny. But I didn’t know whether we would succeed. "

Ulvaeus’s initial reluctance is in keeping with his longstanding unwillingness to exploit his group’s history for a quick buck. Unlike many of his ’70s peers, he’s turned down ridiculously lucrative offers to reunite with his former bandmates — Andersson (with whom he’s collaborated on writing musicals since Abba’s split), Fältskog, and singer Ani-Frid Lyngstad — for what would no doubt be an enormously profitable tour.

" Well, we don’t need the money, " he says with a mischievous chuckle. " I could always see us getting together at some point, but it just never happened. And now, there needs to be motivation that’s just not there. We split up because there was a lack of energy all of a sudden. [Andersson and Lyngstad had also divorced by the end of Abba’s run.] I don’t think we can deliver something spectacular — and I’d hate to disappoint all those people out there. "

There was no middle ground with Abba. You either loved them or loathed them (writing in The New Rolling Stone Record Guide in 1983, critic Ken Tucker cautioned that though the band’s greatest hits were of " the highest quality, " they were also " prone to induce both sleep and cavities " ). Yet Abba all but ruled the worldwide pop charts during the Me Decade. " Dancing Queen, " the group’s biggest seller and its lone US #1 hit, topped the charts in 12 other countries in 1977. " It still sounds very fresh to my eyes, and well-produced, " says Ulvaeus of the band’s catalogue. " Our music might have come across as something very lightweight and camp. But I always felt that people didn’t see underneath the surface, that we had the same serious attitude as Led Zeppelin. It’s just that our music was different. "

When the anti-disco, anti-’70s backlash hit, Abba might as well have been wearing red bullseyes on the front of their white silk shirts. " You’re never prepared for that kind of thing. And yes, sometimes I was hurt by that — by, you know, rock critics. Especially those know-it-alls who can predict that this group will be dead within one and a half years. " Ulvaeus says this with the hearty laugh of somebody who’s had the last one.

Mamma Mia! opens at the Colonial Theatre this Friday, August 17, and runs through September 23. Tickets are $27 to $82. Call Ticketmaster at (617) 931-2787.

Issue Date: August 16-23, 2001