Audioslave was an American hard rock supergroup who formed in Los Angeles, California in 2001. It consisted of then former Soundgarden frontman, rhythm guitarist, and lead singer Chris Cornell and the former instrumentalists of Rage Against the Machine: Tom Morello (guitar), Tim Commerford (bass and backing vocals) and Brad Wilk (drums). Critics initially described Audioslave as an amalgamation of Rage Against the Machine and Soundgarden, but by the band's second album, Out of Exile, it was noted that they had established a separate identity.

The band's trademark sound was created by blending 1970s hard rock with 1990s alternative rock. Moreover, Morello incorporated his well-known, unconventional guitar solos into this mix. As with Rage Against the Machine, the band prided themselves on the fact that all sounds on their albums were produced using only guitar, bass, drums and vocals.

After Audioslave released three successful albums, received three Grammy nominations, and became the first American rock band to perform an open-air concert in Cuba, Cornell issued a statement in February 2007 announcing that he was permanently leaving the band "due to irresolvable personality conflicts as well as musical differences". As the other three members were busy with the Rage Against the Machine reunion, and Morello and Cornell had each released solo albums in 2007, Audioslave was officially disbanded.

Audioslave's history dates back to October 18, 2000, when lead vocalist Zack de la Rocha announced he was leaving Rage Against the Machine. This led to the band's break-up, but the remaining three members of the band decided to stay together and announced plans to continue with a new vocalist. Several vocalists jammed with the three, including B-Real of Cypress Hill, but they did not want another rapper or anybody who sounded like de la Rocha. Music producer and friend Rick Rubin later suggested that they play with Chris Cornell, the ex-frontman of Soundgarden. Rubin also persuaded the three of them to go into group therapy with performance coach Phil Towle after the break-up. Rubin was confident that with the right new voice Rage Against the Machine had the potential to become a better band; he believed "it could turn into a Yardbirds-into-Led Zeppelin scenario". Commerford later credited Rubin for being the catalyst that brought Audioslave together, he called him "the angel at the crossroads because if it wasn't for him I wouldn't be here today".

The chemistry between Cornell and the other three was immediately apparent; as Morello described: "He stepped to the microphone and sang the song and I couldn't believe it. It didn't just sound good. It didn't sound great. It sounded transcendent. And ... when there is an irreplaceable chemistry from the first moment, you can't deny it." The quartet wrote 21 songs during 19 days of rehearsal, and began working in the studio in late May 2001 with Rubin as producer, while sorting out the label and management issues.

The original idea for the band's name was "Civilian", but it was dropped when members found out that it was already taken. Morello later discredited the story, contradicting Commerford and Cornell, and commented that "Civilian" was merely a rumor circulating at the time; he stated: "The band has only ever had one name and that is Audioslave.

By combining '70s style hard rock riffing with alternative rock, Audioslave created a distinctive sound. This mix was driven by Cornell's wide vocal range, Morello's innovative guitar solos and the rhythm section of Wilk and Commerford. Morello, although stating he "never felt musically limited" in Rage Against the Machine, did say that he had "a lot more scope to explore with Audioslave" and a "wider musical territory". This meant that the instrumentalists had the opportunity to write slow and melodic songs, something they had not done before.

As opposed to de la Rocha's lyrics, Cornell's were mostly apolitical; Morello referred to them as "haunted, existential poetry". They were characterised by his cryptic approach, often dealing with themes of existentialism, love, hedonism, spirituality and Christianity. Audioslave's first two albums drew influences from 1970s hard rock such as Led Zeppelin and Black Sabbath and from the members' previous bands (the alternative metal of Soundgarden and the funk metal of Rage Against the Machine). For Revelations, which was influenced by 1960s and '70s funk, soul and R&B music, Morello used vintage guitars and amplifiers and Cornell adopted his "seventies funk and R&B-flavor vocals". The guitarist also cited Sly & the Family Stone, James Brown and Funkadelic as a reason for the funk overtones on the album.

Just as Rage Against the Machine did, Audioslave also included the statement "All sounds made by guitar, bass, drums and vocals" in their albums' booklets as Morello's guitar work often caused listeners to believe that the band used samples, synthesiser effects or different turntable techniques to produce certain sounds.

While Rage Against the Machine's music was politically influenced, Audioslave's originally was not. Cornell stated he did not want to become the new singer of Rage Against the Machine or any political band, but he would play benefits the other band members wanted to play. Despite his reluctance to write political lyrics, he himself never discounted the possibility; he already touched upon political issues in Audioslave's "Set It Off"a song inspired by 1999's WTO riots (the "Battle of Seattle")-then later wrote an anti-war song, "Sound of a Gun", and what Morello called "the most political song Audioslave's ever written", "Wide Awake" for Revelations. "Wide Awake" was an attack on the Bush administration's failure to act over the consequences of Hurricane Katrina.

The band was openly anti-Bush and against the Iraq War from the beginning; on March 17, 2003, only hours after President Bush announced plans to invade Iraq, the band performed live in Hollywood with messages reading "How many Iraqis per gallon?" and "Somewhere in Texas, a Village is Missing an Idiot", scrolled across the stage. The music video for "Doesn't Remind Me" was also critical of the Iraq war. Wilk called Bush "a fucking scam" in an interview, criticizing the Bush administration's rationale for war in Iraq.

During the time of the second album's release several politically-charged Rage Against the Machine songs resurfaced in Audioslave's live set. Although the members committed to not making political statements during their Cuba tour, Commerford stated in an interview that the concert made Audioslave more politically active than Rage Against the Machine ever was. While in Cuba, Cornell said that he takes "every aspect of human life" into consideration, when it comes to writing lyrics, and that he would write about the experience in a song, or more songs. This culminated in the political influences on Revelations, although he did not write about Cuba specifically. He asserted that he felt Audioslave can be a band like U2, which is "not overtly political, but Bono gets a lot done". That year, the band played at two more concerts organized to raise political awareness: Live 8, which aimed to end global poverty, and the Hurricane Katrina benefit concert, ReAct Now: Music & Relief.

Audioslave was prominently involved in the Axis of Justice, a non-profit organization formed by Tom Morello and System of a Down's Serj Tankian to "bring together musicians, fans of music, and grassroots political organizations to fight for social justice". Axis of Justice tents were set up at almost every Audioslave show, and with the exception of Commerford all band members appeared on the Concert Series Volume 1 CD/DVD charity album released in 2004.