NEXT weekend, four 21-year-olds from Sheffield take up a twonight residency at Malahide Castle. Arguably the biggest indie band in the world - if that's not something of a contradiction - Arctic Monkeys have authored the most incredible story in 21st century music, and possibly beyond. The brace of Dublin gigs will act as a warm-up to their headline concert at Glastonbury which tops an 18month rise filled with record-breaking feats, number ones, sacked members and changing the way the rock music industry operates.

It began in Christmas 2001 when Alex Turner and Jamie Cook, two skinny schoolboys from the High Green suburb of Sheffield, received guitars as presents from Santa. Their friend Andy Nicholson learned to play bass guitar (Turner and Cook left school a year later aged 16) and another Stockbridge schoolmate, Matt Helders, bought a drum kit because of a gap in their proposed band. Turner, a quiet, unexcitable only-child born to two teachers, began to write the lyrics, a task no one in the band would admit to doing in case they were slagged. What came from his pen was a witty, acerbic, depressed, realist social commentary on the drunken lives of teens in Sheffield that has earned him the hand-medown crown worn by Jarvis Cocker and Morrissey before him.

Arctic Monkeys played their first gig four years ago this week, and after a while began to transfer their demos onto CDs, giving them out free to fans at their early gigs. Everyone who got one went home and uploaded the tracks online, sparking a method of distribution that had been outlawed by the music industry since the collapse of the internet file-sharing network Napster.

And then the buzz grew. Despite the fact that they hadn't signed a record deal or even released a single, Arctic Monkeys became a very hot ticket. In 2005, the NME named Turner the coolest man in rock. Since then, their success has been attributed to the social networking site MySpace, when it was in fact down to a rather old-fashioned system of swapping songs, with their tracks gradually reaching a wider and wider base. This grassroots system has changed, somewhat, the manner in which emerging bands are promoted, with many now not bothering with any platform other than MySpace to launch and publicise themselves, along with allowing their songs to be downloaded for free.

Their early shows were typified by an awkward stance of high-strapped guitars with each member looking at their fingering, as they were still learning how to play. Nevertheless, the fans were singing back each word of songs that in some cases the band itself had not even perfected, thanks to the online file-sharing of their tracks.

Then, like now, there was very little banter or showboating, just four young men playing fast rock with lyrics about fake tan, drunken text messages, even drunker taxi rides, scraps with bouncers, and various types of trainers.

They reluctantly let themselves be wined and dined by record labels, who were keen to capitalise on the mysterious success that had surrounded the band.

Their indifferent attitude to the music industry became something of a legendary defiance. They refused record company scouts spots on the guest list for their gigs, and often forced industry heads to split the bill with them at restaurants and bars. Eventually, they signed to Domino - home of Franz Ferdinand - and released the indie anthem 'I Bet You Look Good On The Dancefloor' in October 2005.

It went straight to No.1, with no advertising or promotion. Their debut album Whatever People Say I Am, That's What I'm Not, released in January 2006, became the fastestselling British album of all time. Gordon Brown, Oasis and Kate Moss lined up with kudos, as did the critics, and the record earned five stars in almost every publication of note. Three months later, they released an EP titled Who The F**k Are Arctic Monkeys? in reaction to the hype surrounding the band.

The week the album was released, they played the NME tour in the Ambassador in Dublin, supporting Newcastle band Maximo Park, with which Turner shares the peculiarity of 'Park's lead singer Paul Smith of singing in a broad native accent. Although Arctic Monkeys weren't headlining, there was no doubt who the crowd were there to see, and many left before Maximo Park had even taken to the stage.

Relentless touring followed, and a rapturous response in the US (before the tour, bass player Andy Nicholson was replaced by Nick O'Malley from Sheffield band The Dodgems) where audiences are more infatuated with British indie and pop than ever. Their live shows remained bare and sparse, with no light effects or dramatics.

Turner's observations on the trials of working-class teenage drunkenness, hen parties, prostitution, awkward love affairs and anger secured the band the Mercury Music Prize that year. Following rather surly appearances on Popworld on Channel 4, Arctic Monkeys subsequently refused to play on any British television programme, includingTop Of The Pops and CD: UK, adding to their uncertain relationship with the media.

The band have been described in interviews as insular and mute, uttering monosyllables as answers, with only the cockier Jamie Cook occasionally coming out with something worth printing. Their reluctance to engage with journalists and the media in general has earned them some criticism, with Turner now being described in equal parts as surly rather than shy. Predictably, he says he doesn't care.

At the Brit awards last year, they sent a member of American indie band We Are Scientists to accept their award for Best British Breakthrough Act. And this year, they again refused to attend, instead sending a video acceptance speech, while dressed as characters fromThe Wizard of Oz and the Village People, for the award for Best Album.

On 29 April, their second album Favourite Worst Nightmare (Turner toyed with the idea of calling it 'What Are You Going To Sing About Now That You Don't Get Thrown Out Of Clubs Anymore') went to number one. A mistake by iTunes in the online release meant that the album was released as tracks, not a full record, and as a result, all 12 tracks ended up in the top 200, again illustrating - if by accident - their chart prowess.

Turner, and indeed the band themselves, still remain something of an enigma. They've all bought houses near to their parents' homes in Sheffield, and refuse to move to London. Their MySpace website still reads "don't believe the hype" as a headline - although tell that to the thousands who will gather in north Dublin to send them on their way to Glastonbury. Few anecdotes exist of the band's drunken rockstar moments, illicit affairs or tales of drug use - outside of their lyrics, that is. "It's just good tunes, " Turner said upon winning the Mercury Music Prize, "there are no tricks."

C.V.

Born: 2002, Sheffield, UK Members: Alex Turner, Jamie Cook, Nick O'Malley and Matt Helders In the news: Because they're playing two sell-out shows at Dublin's Malahide Castle next Saturday and Sunday