It boggles the mind as much today as it did 30 years ago when four unassuming rock bands from Seattle captured the hearts and minds of the entire world, forever changing the music industry. Soundgarden was first out of the gate. The Chris Cornell-fronted band had several years of indie success under its belt before signing to a major label in 1989. Its second album for A&M, “Badmotorfinger,” was scheduled for release on Sept. 24, 1991. Alice In Chains had also jumped to the majors, inking a deal with Columbia in 1989 that led to a mainstream breakthrough the following year via the single “Man in a Box.” Nirvana, local darlings thanks to 1989’s “Bleach,” released by Sub Pop, had signed with Geffen offshoot DGC in 1990. The band’s new LP, “Nevermind,” was also due out Sept. 24, and those in the scene who’d heard advance cassettes of it were cautiously optimistic about its potential commercial fortunes.

But there was another of Seattle’s Big Four ready to make some noise. Pearl Jam, formed by members of battle-tested Pacific Northwest groups such as Green River and Mother Love Bone, and fronted by an unknown San Diego transplant named Eddie Vedder, entered the fray with its debut album, “Ten,” on Aug. 27 of that year. A slow seller at first, “Ten” went on to move 13 million copies and became one of the greatest debut rock albums of all time.

Thirty years in, Pearl Jam is the only one of those bands still standing, and while the commercial heights of “Ten” are far in the rearview, the group remains one of the most in-demand live acts in the world — its last pre-COVID concerts in the U.S. drew 88,000 to Seattle’s Safeco Field, 83,000 to Chicago’s Wrigley Field and another 72,000 to Boston’s Fenway Park in 2018.

The question, then, is how did Pearl Jam turn that corner, when none of its contemporaries could? One explanation comes in the form of an unlikely role model: the Grateful Dead. Although the two acts have little to nothing in common musically, they share a fierce dedication to cultivating a unique and special relationship with their fans, who travel the globe to experience shows that are never the same from night to night. That “you have to be there” spirit has elevated Pearl Jam’s music far beyond its studio origins and into a place its band members admit they never could have expected it to go.

“I’m almost certain people have come to our shows, and the crowd has gone nuts, and they look to the super-fan to their left to ask what’s going on, and they’ll say, ‘They’ve only played that song six times ever’ — that’s just amazing to me,” Pearl Jam bassist Jeff Ament tells Variety. Ament experienced that magic himself when he saw the Dead for the first time in Las Vegas in May 1993, just days after Pearl Jam wrapped sessions for its second album, “Vs.”

As Ament recalls: “I went to those shows with a guy who worked with our trucking company. I wasn’t that familiar with the Dead at all, and a few times each night, the audience just erupted. He’d turn to me and say, oh, they haven’t played this song since 1971. It was incredible. It felt like the whole stadium knew they hadn’t played it since 1971. I thought, that’s what you want. That’s the crowd that any real, living, breathing band wants, because they’re going to push you into some places that keep you alive. Maybe it wasn’t the best version of that song, but it was the highlight of the day for a good chunk of that crowd.”

Pearl Jam had always changed up its setlists from night to night, but with only two albums of material to perform back in 1993, there was a limit to how much variety one could expect. From then onward, the group pushed its catalog to the limit in a live environment, be it debuting tracks that wouldn’t appear on studio albums for years to come or stretching out songs like “Porch” and “Rearviewmirror” into lengthy, psychedelic jams. This gave rise to a thriving, Dead-esque taping community, which was finally sanctioned officially by Vedder from the stage in Phoenix in 1995 and eventually grew into massive authorized live bootleg program in 2000 with the help of Pearl Jam’s then-label, Sony. It was Pearl Jam’s version of the Dead’s beloved “Dick’s Picks” live series, but instead, it featured every show of the 72-date 2000 world tour rather than just a handful.

“We’d go into record stores and find horrible-sounding, Italian bootlegs that cost $40,” Ament says. “We went to Sony and said, ‘We want to put these shows out ourselves.’ They thought we were crazy, but it turned out to be a pretty successful program for them and for us. We knew the fans wanted recordings, so our goal was to put out the best sounding versions we could, with the limited technology we had at the time.”

The bootleg program remains a fixture of the Pearl Jam ecosystem today, with 186 shows previously only available through the band’s Ten Club fan organization recently having been added to streaming services for the first time. The bootlegs are featured daily on SiriusXM’s Pearl Jam Radio, which debuted in 2010 on channel 22, just one spot ahead of the Dead’s own station. And in another nod to “Dick’s Picks,” the band also regularly releases pre-2000 concerts from its archives via the vinyl-oriented “Vault” series, the most recent which is a 2014 show featuring the only front-to-back performance of Pearl Jam’s 1996 album “No Code.” The accompanying concert video is streaming for free on Nugs.net on Aug. 27, the 25th anniversary of that album’s release.

“I don’t think there was ever any direct impulse for Pearl Jam to be more like the Dead or approach their set lists like the Dead, but I remember talking to Jeff early on about how Dead fans would chase that rare song,” says Ten Club head Tim Bierman, who has run the club since 1998. “With both bands, you see how engaged the fans become when they feel like their set list complete-ism gives them a voice and a sense of purpose to build a community. Pearl Jam always had that from the beginning, and that’s what we try to cultivate with the Ten Club.”

It wasn’t fully apparent at the time, but a cosmic bit of torch-passing between the two bands took place in July 1995 at Chicago’s Soldier Field. Jerry Garcia’s final concert with the Dead happened there on July 9; he died a month later at a California rehab facility. On July 11, Pearl Jam played the longest show of its career (30 songs, 155 minutes) at Soldier Field, with local native Vedder joking that there were still remnants of joints on the stage from two nights earlier.

Ament had seen the Dead again over Memorial Day weekend in Seattle that year, and remembers, “the energy was not great, at least compared to the Vegas shows I’d seen in 1993. I remember thinking, wow, they don’t look good. We played in Milwaukee on July 9, so we didn’t get to see them at Soldier Field, but we definitely built that tour leg around the fact that the Dead had a show booked there. When we were trying to build our own shows from nothing during the Ticketmaster debacle, we’d find out where there was a stage already up, because that could save us $50,000 or something.”

In Dead fashion, Pearl Jam went the extra mile at Soldier Field, mainly because “it was one of the rare cases where Eddie was excited to play a bigger venue, which we did not do much at that time,” Ament says. “My main memory is being so fucking nervous, man. We were backstage learning ‘Everyday People’ and other songs we’d never played through amps. We were going out and winging versions of those songs to fill the set list up, because we were playing this huge venue in Eddie’s hometown.”

None of that would have been possible without such a strong band/fan bond. The Dead pioneered the art of direct-to-fan newsletters in the 1970s and mail-order ticketing in the 1980s through its Grateful Dead Ticketing Service, securing deals with promoters to allot as much as 50% of the tickets in a venue to Deadheads. In the ‘90s, as Pearl Jam’s Ten Club was growing exponentially, then-manager Kelly Curtis visited the Dead’s headquarters in San Francisco to get a first-hand look at their operation. That in turn inspired Pearl Jam to expand its own mail-order ticketing system in 2003 to allow members to purchase two tickets to as many shows on a given tour as they wanted to attend, after having previously been limited to only one. In most U.S. cities, that now means thousands upon thousands of Ten Club members have access to some of the best seats in the house for every Pearl Jam performance.

“We’re constantly working on how we can make that experience better and get more tickets into the hands of the fan club members. It really is our goal,” says Bierman. At one point, the club had more than 200,000 active, dues-paying members, and while Bierman politely declines to give a current figure, he says, “enrollment is pretty consistent, and we do see some new interest. We also have quite a few diehards who have been members since the very beginning.”

Those diehards have kept the Dead alive long after Garcia’s death, as the John Mayer-featuring Dead & Co routinely sell out stadiums and amphitheaters where the pre-show tailgate scene is as free-spirited and convivial as it was 50 years ago. “Walking around that parking lot in Vegas was so great,” Ament says. “Half of it was people making jewelry and food, and half of it was Grateful Dead mafia. You could tell right away which was which.” He adds, laughing, “That’s probably what will happen to us. In 20 or 30 years when there are only two of us left, we’ll be out playing with John Mayer and somebody else.”

Although one can certainly have fun tailgating before or after a Pearl Jam show, hardcore fans have been more apt to mirror the band’s commitment to activism by creating charitable organizations of their own. They include Jeff Ament’s Army, Team McCready and the Wishlist Foundation, the latter of which has raised more than $1.5 million since 2004 for environmental, health and social change causes championed by Pearl Jam’s Vitalogy Foundation.

“After this sabbatical we’ve been on, there’s nothing I want to do more now than play music with the guys in front of an audience — to smile and share that love that we feel from the music and the community,” enthuses Ament, who will return to the stage with Pearl Jam Sept. 18 at the Sea.Hear.Now festival in Asbury Park. N.J. “When I think of a Pearl Jam fan, I think of someone who is conscious of their surroundings and is trying to make their own world better. To be in a room with a bunch of like-minded folks singing our songs, that sounds like the best thing in the world to me right now. I can’t wait.”