Known as much for their politics as for their music, Rage Against the Machine nonetheless helped lay the groundwork for the aggression-fueled rock-rap genre. Frontman Zack de la Rocha brought the rap with his aggressive, politically charged rhymes. Tom Morello produced all manner of punk, metal, and funk sounds with his guitar creating a hard-hitting, bombastic sound to match De la Rocha's rhymes.

Both de la Rocha and Morello were born into activist families. De la Rocha, who grew up in suburban Irvine, California, and East L.A., is the son of a painter, Beto, who devoted his work to Chicano causes. Harlem-born Morello was the son of a Kenyan rebel-turned-diplomat father and a white civil-rights activist mother. Morello graduated from Harvard with a social studies degree and moved to California, where he found a kindred political spirit in de la Rocha. With drummer Brad Wilk and bassist Tim Commerford (a friend of de la Rocha's since grade school), they formed Rage Against the Machine in 1991 and released a self-produced 12-song cassette the following year, which quickly won them a deal with Epic. The band did not sign until it was assured full creative control.

Rage Against the Machine (Number 45, 1993) landed the group a spot on the Lollapalooza Tour and spawned the MTV video "Freedom," with which the band hoped to raise support for imprisoned American-Indian activist Leonard Peltier. The album grew in popularity by leaps and bounds, particularly as young fans discovered the adrenaline-fueled "Killing in the Name"—which addresses police corruption and racism — and it's defiant slogan of resistance: "Fuck you! I won't do what you tell me!"

Other causes championed by the band over the course of their career have included death-row inmate Mumia Abu-Jamal's fight for a new trial, the plight of sweatshop workers, and the Zapatista freedom fighters in Chiapas, Mexico. Critics would often question whether or not the band's message was getting through to the majority of their fans, but the success of RATM's second album, Evil Empire(Number One, 1996), proved that the music, at least, was connecting with a sizable audience. The audience was still in force three years later, with The Battle of Los Angeles debuting at Number One and the single "Guerilla Radio" reaching Number 69 in 1999.

The year 2000 proved to be an eventful and tumultuous one for the band. The "Rhyme and Reason" co-headlining tour with the Beastie Boys (in the tradition of Rage's 1997 jaunt with the Wu-Tang Clan) was scrapped due to an injury in the Beastie Boys camp, but a free concert outside the Democratic National Convention in L.A. protesting the two-party political system went off without a hitch — until a handful of protesters began a small riot with police, following the band's set. Less than a month later, Commerford was arrested and charged with assault and resisting arrest after he scaled a stage prop during the MTV Video Music Awards (both charges were dropped when he pleaded guilty to disorderly conduct). In October, shortly after the recording of the Rick Rubin–produced covers album Renegades (Number 14, 2000), de la Rocha announced his sudden departure from the group, citing a communication breakdown.

Morella, Commerford, and Wilk teamed with Soundgarden singer Chris Cornell to form Audioslave, which released three albums: Audioslave (Number seven, 2002), Out of Exile, (Number One, 2005), and Revelations (Number Two, 2006). Cornell quit the band in February, 2007. In April, 2007, Morello released a solo album One Man Revelution under his folk-rock pseudonym, The Nightwatchman.

Later that month, Rage Against The Machine reunited to headline the Coachella Valley Music and Arts Festival, which turned out to be the start of an extensive reunion tour that included a slot headlining the Lollapalooza tour and stops in Europe and Asia.

source - http://www.rollingstone.com/music/artists/rage-against-the-machine/biography