How to Dismantle an Atomic Bomb is the eleventh studio album by Irish rock band U2. It was released on 22 November 2004 in the United Kingdom by Island Records and a day later in the United States by Interscope Records. It was produced by Steve Lillywhite, with additional production from Chris Thomas, Jacknife Lee, Nellee Hooper, Flood, Daniel Lanois, Brian Eno, and Carl Glanville. Much like their previous album All That You Can't Leave Behind (2000), the record exhibits a more mainstream rock sound after the band experimented with alternative rock and dance music in the 1990s.

Looking for a more hard-hitting sound than that of their previous album, U2 began recording How to Dismantle an Atomic Bomb in February 2003 with Thomas. After nine months of work, the band had an album's worth of material ready for release, but they were not satisfied with the results. The group subsequently enlisted Lillywhite to take over as producer in Dublin in January 2004. Lillywhite, along with his assistant Lee, spent six months with the band reworking songs and encouraging better performances. U2 lead singer Bono described the album as "our first rock album. It's taken us twenty years or whatever it is, but this is our first rock album." Thematically, the record touches on life, death, love, war, faith, and family.

How to Dismantle an Atomic Bomb received generally positive reviews from critics and reached number one in 34 countries, including the US, where first-week sales of 840,000 copies nearly doubled the band's previous personal best. The album and its singles won all eight Grammy Awards for which they were nominated. It was also the fourth-highest-selling album of 2004, with almost ten million copies sold, and it yielded several successful singles, such as "Vertigo", "City of Blinding Lights", and "Sometimes You Can't Make It on Your Own". The album was included on Rolling Stone's list of the "100 Best Albums of the Decade" at number 68. U2 commemorated the album's 20th anniversary with a remastered re-release, which includes a companion album of tracks from the recording sessions called How to Re-Assemble an Atomic Bomb.

Heading into How to Dismantle an Atomic Bomb, U2's guitarist the Edge said the group felt it was the appropriate moment to explore their early musical inspirations. U2's lead vocalist Bono said in a 2005 interview, "I went back and listened to all the music that made me want to be in a band, right from the Buzzcocks, Siouxsie and the Banshees, Echo & The Bunnymen, all that stuff. And what was interesting is, that was what a lot of people in bands now are listening to anyway. So in a funny way, it made us completely contemporary." U2 also wanted to make a concerted effort to revisit the same creative approach from their formative years: the ethos of the band members playing together in a room, with just guitar, bass, and drums. The Edge said: "The limitations that that creates are an interesting challenge because you have to do it with just those instruments, and dynamics become a hugely important part of the creative process."

Rather than repeat themselves after their previous record, All That You Can't Leave Behind (2000), U2 were seeking a harder-hitting, more guitar-driven rock sound in response to the success of the album's single "Beautiful Day". As a result, they hired producer Chris Thomas, who had worked on some of their favourite records, including Never Mind the Bollocks, Here's the Sex Pistols by the Sex Pistols and early works by Roxy Music. The Edge said that he wanted Thomas to put the same stamp on U2's record that he had done on Never Mind the Bollocks, "The White Album" by the Beatles, and The Dark Side of the Moon by Pink Floyd. U2 began recording with Thomas in February 2003; the Edge said the sessions were intended to have a "visceral band sound", and that he wanted a guitar tone like Steve Jones's on Never Mind the Bollocks. To get into the desired creative mindset, the group continued their "power hour" tradition that began years prior with their long-time producer Daniel Lanois; several times a week, regardless of what they were working on, the band set aside time to improvise new material together, often producing two or three new song ideas. The Edge said this generated intrigue around the new pieces of music and used "the right kind of chaos where a radical element will be the thing that we'll all jump on to work with, whatever it might be".

The Edge said that in retrospect, the group struggled with Thomas at the production helm. They had begun with a lot of basic song ideas that were "out of focus", which they sensed Thomas was not accustomed to. The Edge said when it came to realising their "visceral band in the room" approach, U2 "over-emphasised [their] songwriterly methodology and didn't trust enough the raw energy of what a band can do". He thought they had made progress with Thomas, but upon listening to rough mixes of their material, they realised that their desire to musically "push the chaos further" was being tempered by Thomas's instinct to rein them in, and that the songs sounded "too polite". Late in 2003, the band visited AIR Studios in London to record overdubs with a 20-person string section "to give a few songs some lift". Bassist Adam Clayton called the session the moment "the wheels came off"; he sensed the musicians' lack of enthusiasm for the band's music, saying: "We could read the room. And they were not going, 'Wow, guys, this is really happening!'"

After nine months of work, the band had completed an album's worth of songs. In October 2003, they met in Dublin to review their work. Bono and the Edge believed it was good enough to release; Bono said, "All we needed was the assent of the politburo and the record would have been out for Christmas." Clayton and drummer Larry Mullen Jr., however, disagreed with their bandmates and voted against releasing the record. Mullen said that the songs "had no magic", while Clayton said, "When it comes to signing off on a project, you ask questions like, 'Have we got a first single to open the campaign?' Frankly, we were missing more than just a first single." Clayton and Mullen also felt that All That You Can't Leave Behind had been overpraised, and they considered "Beautiful Day" to be the only hit single that the album generated. Clayton thought that if U2's goal was to continue to be the world's biggest band, they needed three or four hits from their album that could attract new fans.

The group brought in their long-time producer Steve Lillywhite to mediate the disagreement. After they played him the album, Lillywhite assessed that it felt like "it had the weight of the world on its shoulders. It certainly wasn't any fun." After lengthy discussions, Bono and the Edge were convinced that the album needed more work. Bono thought their songs were good but admitted "good won't bring you to tears or make you want to leave your house and tour for a year". Without making any firm decision on the album's producer, the group decided to undertake recording sessions with Lillywhite and see where it led them.