On Sept. 29, 1998, Big Boi and Andre 3000 of OutKast combined zodiac signs and creativity to produce not only their best collective work, but one of the most important albums in hip-hop, Aquemini.

World-wise, wary, alien and earthy, Aquemini is the quintessential OutKast album, coming at a time when fans of their 1994 debut, Southernplaylisticadillacmusic and their outstanding, space-age sophomore 1996 effort, ATLiens, were confused and concerned about Big and Dre's standing as artists and friends.

While on their debut, the group were cohesive, helping to establish the Dungeon Family collective and Organized Noize as creative forces, by the time ATLiens arrived, Dre and Big were clearly on different paths. Dre had morphed into the other-worldly one, deeply introspective and cautious about what vibes he was putting out into the world, and what he was taking in. You can hear Dre's metamorphosis all over ATLiens, especially on tracks like "Elevators (Me & You)" and "Mainstream." If Southernplayalistic signaled Dungeon Family's arrival, ATLiens was Dre's lyrical coming-out party as he emerged as one of the best and most original writers in rap music.

As for Big, he was going through is own personal changes. His aunt Renee, who helped raised him as a teen after he moved from Savannah to Atlanta, had recently passed. He was a father, and struggling with his new role as a man and ambitious artist. And, his longtime partner in rhyme and friendship had just boarded a spaceship off to another land. You can hear Big's questioning and yearning on ATLien on tracks like "Babylon."

That emotion and new vision made ATLiens an important, signature album for 'Kast as they came into their own as men and artists. You could hear the electricity throughout the entire project.

"That’s what makes the group so unfuckwithable. You have two sides of the same coin with different points of view. The shit fun, man," Big explained in a 2016 interview.

But two years later, it seemed that the distance between Big and Dre that became evident on ATLiens had reached new heights. Were they even friends any more? How were they going to make music, with Big Boi leaning heavily into his wise, everyman persona and Dre veering off to Mars with his wandering rhymes and aesthetic?

Those questions carried over to their third album, reaching a fever pitch before its release in 1998. Most of the pondering landed squarely on the shoulders of Dre. After all, he was the one who'd most visibly changed. Were their obvious differences going to push them in separate directions? Would OutKast break up? And if they didn't, what would their new album sound like? Aquemini was the answer.

"It's OutKast Aquemini, another black experience..." 

Literally a merging of their zodiac signs, Aquarius (Big Boi) and Gemini (Andre), the album laid the questions to rest. It was brilliant sonic meshing of their respective sounds and strengths, proving that their individuality could coalesce to create a sound that was futuristic, eerily current, present and other-worldly. They were questioning as often as they were pontificating, lending a humanity to the project that still resonates.

Right from the start, Big and Dre get down to business, shutting up naysayers and perplexed 'Kast fans. On "Return of the "G," one of their best records to date, any doubts about unity between the two are killed.

"Then the question is Big Boi what's up with Andre? / Is he in a cult? Is he on drugs? Is he gay? / When y'all gon' break up? When y'all goin' wake up? / N-gga I'm feelin' better than ever what's wrong with you? You get down!" Dre raps on the opening verse.

“With Big Boi standing by me I knew I had to address some of the shit 'cause I can't have my homeboy looking bad," Dre told Creative Loafing years after the release. "I knew a lotta people felt like Southernplayalistic was some of our hardest work and they felt like we strayed from that. So 'Return of the Gangsta' was trying to give them a sense of, 'Hey, I'm still a regular person.' At the end of the day, you've still got to go through the same neighborhoods so sometimes you have to say stuff to let people know what it is. I'm a man so you can't say some of this stuff to me. The things in that verse were addressing all of that.”

The rest of the album is just as real, relatable and inspiring in its ambition. Dre and Big have always had the unique ability to both relate to and chastise their peers without ever sounding preachy, arrogant or judgmental. They're from the dirt too, they just see the light because they're looking for it. That idea is never clearer than on this album.

It's obvious as the record progresses that this is peak OutKast, everything the group was destined to do lyrically, sonically and conceptually, gelled together on one album in a way that hadn't happened before. It was masterful.

What's maybe the most surprising, is that Organized Noize's production is minimal. While they produced the entirety of OutKast's debut, by the time ATLiens rolled around Big and Dre had learned from their big brothers, and began making a lot of their own beats. With Aquemini, Big and Dre's ascension as producers was complete, and they called on Organized for four of the album's defining tracks—the first (controversial) single "Rosa Parks," "Skew It on the Bar-B" and "Return of the G" among them— the rest of the production is handled by Big, Dre and Mr. DJ.

The sound is dirty and funk-drenched, spiritual and grounded, off-kilter but rooted and relatable. Nothing sounded like it back then. And even now, it still sounds fresh in its differentness.

"Aquemini was just the meshing of both worlds, with me being an Aquarius and him being a Gemini. It was subtle on ATLiens, but by the time we got to Aquemini it was like we had two different visions that were [parallel]. So the thing with us was to always show the team," Big said in 2010.

Aquemini's release came on a momentous day in hip-hop, arriving on the same day as A Tribe Called Quest's long-awaited The Love Movement, Jay-Z's career-changing Vol. 2... Hard Knock Life and the arrival of Black Star via Mos Def (Yasiin Bey) and Talib Kweli. Out of those records, however, Aquemini stands as the most brilliant, lightyears ahead of its time, and impactful both musically and culturally.

"Being an alien is just being yourself, when people don't understand you," Dre explained in 2014, when the duo embarked on one last tour. "We just trying to let everybody know there's a place for everybody in this world. You just gotta find yourself, and be true to yourself. That's how you get prosperous and happy."

Lyrically, Big and Dre were completely in another realm, with life-lessons and analysis that remain relevant. Just listen to the hook on the lead single, "Rosa Parks," the outer space, tingling energy on "Aquemini," the dystopian futuristic "Synthesizer,"  or the storytelling on "The Art of Storytellin' (Pt. 1)." After being disrespected at the '95 Source Awards, and struggling to prove to everyone that the South had always had "somethin' to say," Aquemini was birthed.

"We were the first ones to break through to the North and have them respect us as MCs, our craft, our ability to write lyrics, and have bars," Big Boi explained in 2016. "They had to respect it. He spoke it at the award show because they booed, but we didn’t give a fuck. It pissed us off, and they shouldn’t have did that, because it fueled us and threw gas on the fire. But we were already thinking that, because we had to fight so hard to be recognized."

Agitated and sophisticated, Big and Dre flow through Aquemini with relaxed urgency, and it's captivating.

"I gotta hit The Source, I need my other half a mic / Because that Southerplayalisticadillacmuzik was a classic, right!" –Big Boi, "Skew It On The Bar-B." 

Guest appearances were minimal and served only to enhance the vibe already being created. Check out Cee-Lo and Erykah Badu's aching verses on "Liberation" and Raekwon's charged delivery on "Skew It On the Bar-B."

The album isn't an immediate easy listen. There's no "Hey Ya," "B.O.B." or "Ms. Jackson" on this record, but those kind of hits aren't what makes this album so great and impactful. It's the depth of scope, the concentrated, wary, sometimes downright paranoid musings on culture and society ("Syntheizer"), the intimate tales ("Da Art of Storytellin"), the staccato direction of the music that makes this such an important record.

"Until they close the curtain... it's him and I, Aquemini." 

OutKast's Albums, Ranked