Inductees: Bono (vocals; born May 10, 1960), The Edge (guitar; born August 8, 1961), Adam Clayton (bass; born March 13, 1960), Larry Mullen Jr. (drums; born October 31, 1961)From the beginning, U2 has been a band on a mission. With each album and concert, the Irish quartet has endeavored to create music of lasting worth and substance. At various points in their career U2 have been not only the most popular band in the world but also arguably the most important - although success in their own minds is purely conditional on the caliber of their work. "We had no interest in being the biggest if we weren't the best," guitarist Dave "The Edge" Evans told Rolling Stone in 2004. "That's the only way being the biggest would mean anything."U2's best work - which includes War (1983), The Joshua Tree (1987), Achtung Baby (1991) and All That You Can't Leave Behind (2000) - stand out as true classics in the rock canon. Bono's high-profile work for causes like Third World debt relief and U2's participation in such historic rock-for-charity events as Live Aid and Amnesty International's Conspiracy of Hope tour in have made them something of a beacon for positive change in the world of music.Ultimately, what's set U2 apart is the visionary passion of vocalist Paul "Bono" Hewson and the group's music, which mixes rock's visceral energy with artful atmospherics. U2 has been hugely popular in its first quarter century, yet they've remained a supergroup with an idealistic sense of purpose. Having risen to prominence in the early Eighties - a time when the iconic status of rock stars was routinely challenged by skeptical punks and New Wavers - U2 managed to become a stadium-filling phenomenon without sacrificing credibility.Moreover, they've been given to periodic reinvention, as evidenced by their passage from the politically themed anthems of War to the more ethereal musical landscapes of The Unforgettable Fire (1984), and from the earnest soul-searching of The Joshua Tree to its radical and irreverent successor, Achtung Baby. Underneath it all, they're remained true believers. As Bono told USA Today in 2000, "There is a transcendence that I want from rock… I'm still drunk on the idea that rock and roll can be a force for change. We haven't lost that idea."That idea has been a motivating force from the outset. U2 formed in 1978 when drummer Larry Mullen posted a note on a bulletin board looking to form a band. The group members - Bono, The Edge, Mullen and bassist Adam Clayton - attended Mount Temple High School in Dublin, Ireland. They derived influence from the guitar-driven minimalism and do-it-yourself aesthetic of such punk-rock peers as the Ramones and Sex Pistols. Yet they also aspired to the more serious, message-laden music of songwriters like Pete Townshend and Bruce Springsteen. Early in 1981, with its debut album only months old, Bono confidently predicted a place for U2 in rock's upper echelon. "Even at this stage, I do feel we are meant to be one of the great bands," he told Rolling Stone in 1981. "There's a certain spark, a certain chemistry, that was special about the Stones, the Who and the Beatles, and I think it's also special about U2."They debuted with a three-song EP, U2-3, in 1979 and built a word-of-mouth following in their Irish homeland as a live band, U2 signed with Island Records in 1980. Their debut album, Boy, included the popular track "I Will Follow," the first of many U2 anthems. The basic elements of the U2 sound - The Edge's jittery, effects-laden guitar; Bono's soaring, unrestrained vocals; Clayton's solid, anthemic bass lines; and Mullen's offbeat, hypnotic drums - were already in place at this early juncture. Boy was produced by Steve Lillywhite, who would help shape the group's unique sound on the next two albums as well. Experimental twists would become part of U2's modus operandi, but that core structure has remained their sonic signature.U2's moody second album, October, reflected the difficulty of reconciling their religious beliefs with their rising fortunes as rock stars. They even considered disbanding. In the end, U2 decided to put their collective voice to use raising consciousness. On War they focused their energy and honed their message, raging over the strife-torn modern world - specifically, the sectarian strife in their native Ireland - in such testaments as "Sunday Bloody Sunday" and "New Year's Day." War has been termed "a powerful fusion of politics and militant rock and roll" and even the band called it "a positive protest record." Bono referred to "Sunday Bloody Sunday" as "a song of hope and a song of disgust," and Mullen noted it was "the first time we ever really made a statement."With this album, U2 vaulted into a class with the impassioned, topical likes of the Clash and Bruce Springsteen. "Sunday Bloody Sunday" gave U2 their first #1 hit in the U.K., and the album entered the U.K. charts at #1, appropriately enough, on St. Patrick's Day. War reached #12 in the U.S. and was their first album to go platinum.U2 followed War with Under a Blood Red Sky, a live album recorded in Colorado, Boston and Germany. Between Bono's onstage fervor and the band's rousing majesty, U2 built up a monumental head of steam as a live act. Bono would wave a large white flag - symbolizing a flag "drained of all color" - during their show, symbolizing the "one world" concept he believed in and advocated. Under a Blood Red Sky, released as an album and video, consolidated U2's strengths and closed a chapter on the remarkable first stage of their career.Their fourth studio album, The Unforgettable Fire (1984), saw U2 move toward a more ghostly, cinematic sound. The group selected Brian Eno and Daniel Lanois as producers, and the results were more abstract and experimental than previous albums. The key track was "Pride (In the Name of Love)," a pacifistic anthem inspired by the life of Martin Luther King, Jr. U2 toured heavily in its wake, headlining arenas and stadiums and performing one of the most memorable sets at Live Aid in July 1985.In March 1987, U2 released The Joshua Tree, an album that captivated, inspired and united the rock and roll audience like no other (save Bruce Springsteen's Born in the U.S.A.) in the Eighties. Both thoughtful and powerful, it was preoccupied with spiritual survival in a barren, conflict-ridden age. Giving rise to a pair of #1 singles - "With or Without You" and "I Still Haven't Found What I'm Looking For" - The Joshua Tree topped the charts for nine weeks. It went on to win a Grammy for Album of the Year, and Rolling Stone judged it the third best album of the Eighties. The Joshua Tree has sold more than 15 million copies worldwide and in 1995 qualified for diamond certification (10 million sold) in the U.S.The accompanying world tour gave rise to Rattle and Hum, a concert film and double album that mixed live and studio material. Among other things, the project revealed the group's fondness for American roots music, as when they collaborated with blues guitarist B.B. King on "When Love Comes to Town." Drafting on The Joshua Tree's formidable coattails, Rattle and Hum also went to #1 (for six weeks) and spun off a pair of hit singles, "Desire" and "Angel of Harlem."The Joshua Tree elevated U2 to superstar status but also provoked one of the most radical musical detours by a major rock band. At the end of the decade, Bono stated that U2 planned to "go away and dream it all up again." True to his word, U2 came together in Berlin in late 1990 to record Achtung Baby, a brazenly experimental about-face that Bono has described as "the sound of us chopping down The Joshua Tree." Triggering a creative renaissance, it marked U2's effort to undercut its own sense of seriousness and joint the postmodern party. To a degree, they deliberately went from iconic to ironic (although "One" ranks with their most heartfelt songs). Coproducer Brian Eno referred to "the scope of its inspirations: psychedelia, glam, R&B and soul" and characterized it as "a long step taken with confidence."Recorded in Berlin, Achtung Baby sold more than 10 million copies worldwide and set U2 on a course for the Nineties. It and the discs that followed - Zooropa (1993) and Pop (1997) - form a kind of triptych. The group embraced the messy state of the war-torn, media-saturated world with a grim sense of celebration, as Bono created a handful of devilish alter egos - including "The Fly" and "Mr. MacPhisto, the Last Rock Star" - for the stage. Zooropa, an adjunct and coda to Achtung Baby, was recorded in Dublin during a break between legs of the Zoo TV tour.On Pop, U2 delved into electronica - loops, samples, beats - without reservation. Some of that album's material actually got worked up from jamming with DJs. Pop was the group's most cutting-edge album to date. U2 were no longer "the world's loudest folk band," which is how Bono described the group's Eighties persona in hindsight. Instead of mourning the ruins, they were now dancing in them.In the Nineties, U2's live shows served as oversized spectacles. Their Zoo TV and PopMart tours were among the most ambitious ever undertaken. They played to more than five million people on the former outing alone. PopMart, which followed Pop's release, satirized rampant consumerism with a set designed to look like a "giant, sci-fi disco supermarket." A hundred-foot high golden arch, fifteen-foot mirror-ball lemon and twelve-foot stuffed olive were among the oversized stage props. The group and its 200-member crew dragged 1,200 tons of equipment from gig to gig. It was truly over the top, which was exactly the point. If Zoo TV was "the Sgt. Pepper of rock tours," than PopMart was its gaudy Graceland.Not surprisingly, after spending most of a decade making their point - which might be described as "defeating the devil by singing his song" - U2 got back to basics. Their first album of the new millennium, All That You Can't Leave Behind (2000), was a return to the classic U2 sound, warm and open-hearted in a way that recalled The Joshua Tree while at the same time streaked with the sort of textures and accents they'd mastered in their adventuresome Nineties spree. All That You Can't Leave Behind topped the charts in 32 countries and won seven Grammys, including Song of the Year for "Beautiful Day."Late in 2004 they continued on this path with How to Dismantle an Atomic Bomb, which yielded the heady hit "Vertigo" and contained some of Bono's most personal lyrics. In a sense, the album brought U2 full circle, returning them to the autobiography of Boy. Yet in the years between those albums they'd grown from teenagers to adults, inevitably losing friends and relatives along the way. Bono suggested that How to Dismantle an Atomic Bomb album could have well been titled Man. In 2005, Bruce Springsteen inducted U2 into the Rock and Roll Hall of Fame. Then, in 2008, the band issued the movie U2 3D, which was filmed during the Vertigo tour. That film is shown in the Foster Theater at the Rock and Roll Hall of Fame and Museum.In 2009, U2 released another studio album, No Line on the Horizon. Rolling Stone gave the album a five-star review. The band hit the road in support of the album with its U2 360® tour. The show featured the largest concert stage in the history of rock and roll. The tour continued through July 2011 and attracted a total audience of more than 7 million fans. While much had changed, important things remained the same: U2 comprises the same four musicians, still holding fast to principles and making inspirational music more than 30 years after their humble beginnings in a Dublin high school.