STOCKHOLM.- The small, tranquil island of Skeppsholmen holds a handful of the Swedish capital’s artistic treasures: Moderna Museet, the theater group Teater Galeasen and the converted red brick warehouse just steps from a waterfront promenade where Benny Andersson has his personal studio. He tucked a packet of the oral tobacco snus in his mouth as Bjorn Ulvaeus sipped coffee in one of its sunbathed rooms earlier this month, the two musicians surrounded by a grand piano, a small selection of synths and an assortment of framed photographs that were perched behind a computer screen.

For the first time since the Reagan administration, the pair were discussing a new album by their band, Abba — an album one of the biggest international pop acts in history somehow made in secret, with all four of its original members congregating nearly four decades after giving their last public performance.

“We took a break in the spring of 1982 and now we’ve decided it’s time to end it,” the group said in a statement in September. The response was thunderous. “Abba is another vessel, isn’t it?” Ulvaeus marveled at the studio, just steps from the larger one where they completed their clandestine LP. “We did this thing and we are on the front page of every paper in the world.”

In a country known for producing towering figures in pop music (Avicii, hitmaker Max Martin, Robyn, Roxette) Abba still looms the largest, and even has its own permanent museum. Between 1973 and 1981, the quartet — which includes singers Agnetha Faltskog and Anni-Frid Lyngstad — released eight studio albums filled with meticulously crafted melodies, harmonies and strings that have generated 20 hits on Billboard’s Hot 100 chart, sold tens of millions of albums around the world and built a passionate fan base.

But its paradigm-shifting impact can’t be measured only in numbers: The group was known for taking risks with technology and the use of its songs. Starting in the mid-1970s, it was among the first acts to make elaborate promotional mini-films — we’d call them music videos now — most of them directed by Lasse Hallstrom. Its 1981 album “The Visitors” is generally acknowledged as the first commercial release on compact disc. The 1999 jukebox musical “Mamma Mia!” paired the group’s hits with an unrelated plot, sparking a slew of imitators and two film adaptations that brought us the spectacle of Meryl Streep singing “Dancing Queen.”

Now Abba is risking perhaps its most valuable asset — its legacy — by not only releasing a fresh addition to its catalog, but creating a stage show that features none of its members in the flesh. Starting in a custom-built London venue next May, the group will perform as highly sophisticated avatars (or in this case, Abbatars) designed to replicate their 1979 look — the era of feathered hair and flamboyant stage wear.

Andersson, 74, and Ulvaeus, 76, two of the most low-key men in a high-stress industry, said they were genuinely surprised, and possibly a little relieved, by the excitement that greeted the new album’s announcement. (The 10-track “Voyage,” which shares its name with the forthcoming live show, is out Nov. 5 on Capitol.)

“We had no idea it would be so well received,” Ulvaeus said. “You just take a chance, you risk a thumping.” It was hard to tell if he was echoing the title of one of Abba’s most famous songs on purpose; these guys have a way with dry humor.

Still, they might have had an inkling a reunion would spur interest. Since it went offline in 1982, Abba has continued to thrive. Conversations about pop have shifted over the decades, helping the group overcome the “cheesy Europop” tag that often stuck to it during its 1970s prime — “We have met the enemy and they are them,” American critic Robert Christgau wrote in 1979. Abba is now widely respected as a purveyor of sophisticated pop craftsmanship, and its enduring popularity transcends generations and borders.

“Abba is simply one of the biggest groups in the history of popular music,” Michelle Jubelirer, president and chief operating officer of Capitol Music Group, wrote in an email. “They are truly a global phenomenon, and have been so since they won the Eurovision Song Contest in 1974 with ‘Waterloo.’ ”

And every decade or so, something has rekindled interest, starting with the 1992 compilation “Abba Gold,” which is still on the British charts more than 1,000 weeks after its release (I wrote the liner notes to a 2010 reissue). The band’s classic songcraft and studio wizardry continues to bridge musical allegiances, drawing fans as diverse as Elvis Costello, Carly Rae Jepsen, Jarvis Cocker, Kylie Minogue and Dave Grohl. Just ask Madonna, who directly appealed to the group for a sample of “Gimme! Gimme! Gimme! (A Man After Midnight)” for her 2005 hit “Hung Up.”

Andersson and Ulvaeus could easily have just sat on their piles of kronor, with the knowledge that their place in the record books was secure: “What is there to prove?” Andersson said. “They’ll still play ‘Dancing Queen’ next year.”

Ulvaeus chortled. The duo still complement each other almost comically perfectly: Andersson is a musician’s musician who goes to his studio almost every day (and drives an ultracompact Toyota). Ulvaeus, who has always had an entrepreneurial bent, continues to pursue various projects with his production and hospitality company Pophouse Entertainment (and pilots a red Tesla).

Because there was no pressure to reunite, the pair say there was no grand plan for an album: It just kind of happened when four friends realized they still enjoyed making music together.

It all started about five years ago, when Simon Fuller, the producer behind the “Idol” franchise and the Spice Girls, pitched a show starring 3D reproductions of the group’s members “singing” the original vocal tracks backed by a live band.

“It was an easy choice (for me) to empower them to be the first important group to truly embrace the possibilities of the virtual world,” Fuller said in an email. “Abba’s music appeals to all generations unlike any group since the Beatles.”

The project also had appealing practical benefits for people unwilling to submit to the grind of big concerts.

“What interested us was the idea that we could send them out while we can be at home cooking or walking the dog,” Andersson said.

The pair traveled to Las Vegas to check out the hologram used in the Cirque du Soleil show “Michael Jackson ONE,” and their main takeaway was that they would have to do roughly a million times better. The visual-effects company Industrial Light & Magic, of “Star Wars” fame, assured them it could happen. (Fuller is no longer involved in the project.)

Naturally, “the girls,” as seemingly everybody in the band’s close circles good-naturedly calls Faltskog, 71, and Lyngstad, 75, had to be onboard, especially since the process would involve weeks of motion capture. “They said ‘OK, if that’s it,’ ” Andersson recalled. “‘We don’t want to go on the road. We don’t want to do TV interviews and meet journalists.’ ” (They kept their word and didn’t participate in this story.)

Andersson and Ulvaeus decided that the Abbatars should have some fresh material because that’s what would have happened before a tour back in the day. In 2017 Faltskog, who lives outside Stockholm, and Lyngstad, who lives in Switzerland, traveled to RMV studio, 100 yards from Andersson’s base on Skeppsholmen. There, they put down their vocals on the ballad “I Still Have Faith in You” and the string-laden disco of “Don’t Shut Me Down.” The two singers, who have been out of the music business for several years, picked up right where they left off.




“They come in and they just, you know, ‘Here you go guys, we can still do this,’ ” Andersson said. “Amazing.”

Faltskog and Lyngstad weren’t the only ones beckoned to work. “Benny called me saying something like, ‘Can you come to the studio, we’re thinking of making one or two songs with the old band?’ ” the guitarist Lasse Wellander, who has been working with the group since its self-titled album from 1975, wrote in an email. “At first I didn’t understand what he meant, then I realized he actually meant Abba!”

The original plan was to do just those two tracks, but they kept going. “We said, ‘Shouldn’t we write a few other songs, just for fun?’ ” Andersson recalled. “And the girls said, ‘Yeah, that will be fun.’ So they came in and we had five songs. And we said, ‘Shouldn’t we do a few others? We can release an album.’ ”

There were conversations about how the new LP would fit into a beloved discography. “Part of it was, is this in any way harming the history of Abba, the music of Abba?” said Gorel Hanser, who has worked with the band members since 1969, before they called themselves Abba, and is integral to the group’s management team. She said she thought Andersson addressed those concerns when the idea first arrived for “Mamma Mia!”: ‘“Are we doing it the right way? Are we destroying what we have?’” she said. “But I think it’s been very well taken care of. We don’t leave anything without doing it as best as we possibly can.”

The new songs feature some of Ulvaeus’ most poetically bittersweet lyrics, with references to the difficulty of relationships and separation. “I’ve been through that myself,” he said. “It’s fiction but you know exactly what it’s like.”

For Andersson, coming up with fresh Abba material was a welcome shift. “I think it’s sort of boring to only work on recycling,” he said, inadvertently sparking a back and forth with Ulvaeus — their only disagreement of the day — over his choice of words.

“You call it recycling, I call it transcendent storytelling,” Ulvaeus said. “You can lift, you can do things on other platforms, which is what ‘Voyage’ is: it’s telling a story on another platform. That’s what ‘Mamma Mia!’ is, too,” he continued, referring to the musical. “It’s not recycling.”

In a way the exchange was pure Abba: easygoing, but undergirded by serious concerns. Another chance for debate came up when the two men were discussing their Abbatars. Andersson remarked that Ulvaeus had requested a change to his digital alter ego’s hair because there is only so much 1979 realness anybody can take. When I remarked that it was a great way to rewrite a little bit of history while still being faithful to its spirit, Ulvaeus replied, with a slight smile, “Yes, it’s such an interesting existential question.” (Ulvaeus, known in Sweden for his commitment to atheism and humanism, enjoys such questions, later asking, “So, do you think the American constitution is strong enough to withstand another Republican president?”)

The Andersson-Ulvaeus songwriting bond has withstood intraband divorces and the pressure brought on by critical scorn. (For those who have forgotten: Andersson used to be married to Lyngstad, Ulvaeus to Faltskog.) They have been writing together nonstop since meeting in 1966, and their post-Abba collaborations include songs for Andersson’s band as well as the musicals “Chess” and “Kristina from Duvemåla,” an epic about 19th-century Swedish immigrants to America that includes the rare showstopper about lice.

While the division of labor used to be fluid in the 1970s, it is now much more clear-cut: Andersson comes up with melodies and records demos in his Skeppsholmen lair then sends them to Ulvaeus, who writes the lyrics. Asked how elaborate those demos are, Andersson volunteered to play “Don’t Shut Me Down,” and walked over to his computer. Then he couldn’t find it among his dozens of files, searching “Tina Charles” since the Abba song has a slinky vibe like one of the British singer’s hits.

He eventually unearthed not the demo but the finished backing track, and cranked it up on the immaculate sound system, providing a great example of how crucial Faltskog and Lyngstad’s voices are to Abba’s sonic tapestry.

“All the various successful groups since the ’70s have had more than one singer,” Andersson said, mentioning Eagles and Fleetwood Mac, alongside Abba. “You hear Frida sing one song and then you hear Agnetha sing — it’s like two bands. The dynamics are helped immensely by the fact that there are two. And then when they sing together …”

Their harmonies on the “Voyage” album bear the unmistakable Abba stamp, even if the register is a bit lower than it used to be. Age alone does not account for the difference: “We used to sort of force them to go as high as they could on most of the songs because it gives energy,” Andersson said.

“We urged rather than forced,” Ulvaeus interjected.

A lot has changed in pop in the past 40 years, but “Voyage” makes no attempt to sound like anything other than Abba. “You listen to new records, it’s always so slick,” Andersson said. “There’s nothing moving aside of the exact rhythm. I don’t do that — I do it by free hand.”

The approach helps makes the new album feel timeless. “Nowadays you can edit anything, but they didn’t,” drummer Per Lindvall, who has been collaborating with Andersson and Ulvaeus since the song “Super Trouper” in 1980 and plays on the new album, said on the phone. “They also haven’t been pitching the vocals to death. It’s part of the unique Abba sound.”

The new show — in which the two men have invested “a big chunk,” according to Andersson, whose son Ludvig is one of its producers — did require a bit more 21st-century technology, including five weeks of motion capture. That involved squeezing into tight suits covered in sensors, and required Andersson and Ulvaeus to shave their beloved beards.

As more pieces of the “Voyage” project fell into place over the past couple of years, the former Klaxons frontman James Righton was enlisted to recruit the Abbatars’ live backing band. Its 10 members include Victoria Hesketh, 37, who performs as Little Boots. In early 2020, she practiced with the newly formed ensemble in Stockholm, under Andersson’s tutelage.

“It was a strange combination of being pushed technically so hard, but at the same time being so full of joy in every moment,” she said in a phone interview. “I could see Benny chuckling to himself behind the mixing desk.”

Four decades ago, this long, improbable journey was unimaginable for four Swedes. “You have to understand how impossible it seemed right before Abba to have hit records in England and the U.S.,” Ulvaeus said of the pop landscape before the internet globalized it. “It was absolutely not in the cards.”

Yet not only did Abba break down barriers for musicians around the world, it did it with the matter-of-fact pragmatism of artisans — which is what its members remain at heart. “The thing is, it has always been like day-to-day work, even then,” Andersson said. “We would write the songs, hope that something good will come out, go to the studio, record those songs. And then we wrote some more. Exactly the same as now: It’s not about anything else than trying to come up with something good, and see what happens.”

This article originally appeared in The New York Times.