"YOU GOT Me" is the song that lifted the Roots from the hip-hop underground and turned the Philadelphia group into stars this year. As the band's live rhythm section lays down a slinky funk groove, the tune describes a new love affair trying to find its legs. Tariq "Black Thought" Trotter's jittery, punchy rap evokes the problems and uncertainties of modern romance, but guest star Erykah Badu sings a melodic, R&B chorus, reassuring her lover that everything is going to be alright.

This tug-of-war between anxiety and assurance reaches a climax in the coda, where Badu improvises dreamy crooning over a jagged drums-and-bass break by drummer Ahmir "?uestlove" Thompson and bassist Leonard "Hub" Hubbard. The single carried the accompanying album, "Things Fall Apart" (MCA), to platinum status, but there was a lot more to the Roots than a catchy pop hook and a celebrity cameo.

The Roots confirmed as much when they released their second album of 1999, "Come Alive" (MCA), a collection of concert performances in New York and Europe. This disc proved three things about the Roots: These musicians don't need samples to sound as tight on stage as in the studio; their songwriting is strong enough to benefit from new arrangements and off-the-cuff improvisation; and the group has been good enough long enough to deserve such a career retrospective.

"We have a real career," asserts Thompson. "Cats out here are wondering why they're not making it past their second record, and it's because they're not treating it like a business. I wake up every day at six and get on the computer for two hours. We have to rehearse; we have to do interviews; we have to do studio mixes; we have to do store visits. It's a job.

"If you have to have a meeting with a record company executive, you have to be there on time. If Spike Lee wants you in his film, you have to be there at 5 a.m. Maybe you want to go see `Being John Malkovich,' but you can't because you have to work. Maybe you want to take your girlfriend to Paris, but you can't because you have to work."

The Roots, who perform at the 9:30 club on Wednesday and Thursday, have played more than 200 shows a year since 1993, and they deserve their reputation as the best live act in hip-hop.

Because the group is a self-contained unit with live drums, bass and keyboards, they avoid the tinny, canned sound of so many hip-hop shows. Moreover, the live musicians can interact with lead rapper Trotter in a way that pre-recorded tracks never could.

"What we do is so natural," insists Thompson. "For the most part, cats rely on samples because they want what we have, which is the ability to play. What we do is what they're trying to recapture. We know how to program and sample -- and sometimes we sample from our own live jams -- but we're musicians. Each of us has been practicing his craft for 20 years. We wouldn't do it any other way."

You can hear the advantages of this approach on the new, eight-minute live version of "You Got Me." Jill Scott, who wrote the original chorus, sings it herself on the new album and gives it a fuller gospel sound than Badu did. Trotter sounds more aggressive himself and changes some lyrics to accommodate Scott's approach. Kamal's electric-piano fills are more prominent this time, and the drums-and-bass section builds to a bigger climax before segueing into a longer, freer coda where the Roots's jazzy inclinations come to the fore. Only a hip-hop band with such skilled live musicians could have changed a song so much so successfully.

"I'm one of a handful of people in the world who do what I do," claims Thompson. "There are a billion MCs, a billion DJs and a billion dancers, but there are very few hip-hop drummers. There's Keith LeBlanc from the Sugar Hill House Band, Pumpkin from Profile Records and Bobby Simmons from Stetsasonic.

"Those are my forefathers. They kept it in the pocket, which is the most important thing. They play with feeling, with dynamics; they know how to clamp down on the cymbal and stop a beat. Very few people can program a drum machine with that kind of feeling. One of them is Jay Dee, who programs for Q-Tip. Another is Prince."

Earlier this month, the Roots joined Vernon Reid, Joan Osborne, P.M. Dawn, Angelique Kidjo, Toshi Reagon and others to perform Prince's 1982 album, "1999," in its entirety at the Brooklyn Academy of Music. The event shed some light on the Roots's own backing tracks, which owe a lot to Prince's sophisticated blend of rock and funk.

"I'm the biggest Prince fan out there," Thompson declares. "He's a genius. He believes in real chords and harmonies, in bridges and codas. He has always pushed the envelope. Prince was more hip-hop in the early '80s than he was when he started doing hip-hop. He used synthesizers and drum machines. He was sexually explicit; his grooves were tight. Prince was singing about who you couldn't bring home to your parents and how the police harassed young people. That sounds like a rapper to me."

When the Roots play at the 9:30 club, it will be one of their last shows for a long time. The group is taking off the first eight months of the new century to recharge its batteries and to pursue some side projects. The whole group will appear in Spike Lee's next film, a television satire called "Bamboozled." Trotter will also star in "Brooklyn Babylon," the next movie from director Marc Levin. Thompson will tour most of the year with D'Angelo to support the album, "Voodoo" (Virgin), which the two men co-wrote and co-produced.

"It's the greatest thing I ever worked on in my life," Thompson says of "Voodoo." "It took us four years to do it, but it was worth it, because we are rewriting the book of soul music. This is not a lover-man record; this is the new millennium funk, a mission. You should see the look on people's faces when I play it for them. They're either totally disgusted or blown away.

"This album will do for soul music what Dylan going electric did for rock and folk music in the '60s. When he first went electric, you remember, people booed and threw things. But he did what he had to do; he couldn't stay in the coffeehouses forever. D'Angelo is rewriting the rules the same way. R&B really needs it, because it's in such sad shape. It's all fast food. This is the broccoli, the bran flakes, the real stuff that's not easy to swallow but that's good for you."

THE ROOTS -- Appearing Wednesday and Thursday at the 9:30 club. n To hear a free Sound Bite from the Roots, call Post-Haste at 202/334-9000 and press 8131. (Prince William residents, call 690-4110.)