The Beastie Boys have always been the standard-bearers of cool with their rap-rock sound. But with 'Hello Nasty,' released on July 14, 1998, the legendary trio showed off their true b-boy style and wit.

As the scratch-and-thrash sounds of Limp Bizkit and Korn started to become novelty in the music world, the Beastie Boys took it back to the old school of beats and rhymes for their fifth album.

'Hello Nasty' -- named after New York-based publicity firm Nasty Little Man for the way the receptionist answered the phone -- featured bombastic beats, rap samples, experimental sounds and the fun lyrical wordplay of Adam "Ad-Rock" Horovitz, Michael "Mike D" Diamond and the late Adam "MCA" Yauch.

The Beasties also introduced a fourth member to the group: DJ Mix Master Mike. The San Francisco native was a three-time DMC World DJ Champion and a wizard behind the turntables. He provided the intricate scratching throughout the album.

"You know, there is nothing planned on the album, we didn't plan anything," said Mike D in a 1998 interview. "All you hear are different sounds, sounds we experimented with, nothing else. Maybe that's our problem: we were so far removed from everything, it was like being underground, really underground, like in a hole in the ground."

The album's first single, 'Intergalactic,' boasts a slew of computer blips and beeps, a robotic vocoder and a head-nodding drumbeat. Lyrically, the Beasties spit non-sensical metaphors and similes about moving the crowd.

"Well, from the family tree of old school hip-hop / Kick off your shoes and relax your socks / The rhymes will spread just like a pox / 'Cause the music is loud like an electric shock," raps MCA.

The accompanying music video, directed by MCA (under the alter ego of Nathanial Hornblower), was a campy tribute to classic Japanese monster movies like 'Godzilla.' The clip was shot in a Japan subway with the Beasties wearing hazmat suits.

The Beastie's second single, 'Body Movin',' which samples Tito Puente's 'Oye Como Va,' is a fantastic song of sample-based rap that's reminiscent of their post-modern excursion on their 1989 classic album, 'Paul's Boutique.'

The group's third single, 'Three MC's and One DJ,' introduced Mix Master Mix behind the turntables and his invention of the tweak scratch.

Another standout track is the "The Negotiation Limerick File,' which features the Beasties rapping five-line limericks.

"I love it when you hit those switches / A curve ball's what my pitch is / So here we -- here we come / Like dum-ditty-dum / I keep all five boroughs in stitches," the trio raps.

Collaborations were only a few on the album. Reggae-dancehall icon Lee "Scratch" Perry appeared on the dub-influenced 'Dr. Lee, PhD,' Miho Hatori (of Cibo Matto) is on 'I Don't Know' and Luscious Jackson's Jill Cunniff sings background vocals on a numbered of songs.

'Hello Nasty' was a very successful album, selling over 4 million copies in the U.S. For their hard work, the Beastie Boys were honored with two Grammy Awards in 1999: one for Best Alternative Music Album and the other for Best Rap Performance by a Duo or Group for 'Intergalactic.'

Fifteen years later, 'Hello Nasty' is still an inventive album, which proved the Beastie Boys could take hip-hop into intergalactic dimensions.

Watch the Beastie Boys' 'Intergalactic' Video

Watch the Beastie Boys' 'Body Movin' Video