A fenced-off compound at an airport in the Los Angeles valley. When you're playing places the size of aircraft hangars, it makes sense to rehearse in one. A small area has been divided off as a band hang-out: it's a reproduction of guitarist Slash's house, with candles, incense and scarf-draped lamps. A Venus flytrap, vegetarian apparently, rattles in its saucer whenever a jet screams over.

Guns N' Roses are getting ready for a tour that should last two years. It sees them headlining Wembley Stadium in August - not bad for a band whose last UK appearances have been at the Marquee club, the Hammersmith Odeon, and a spot one from the bottom on the bill at Castle Donington (the infamous '88 festival when two fans were crushed to death). At the beginning of July, almost exactly four years on, the follow-up to their 15-million-selling debut album, Appetite For Destruction, is finally due for release. Two separate albums, Use Your Illusion I and Use Your Illusion II, will come out on the same day featuring 36 songs between them, ranging from raw-wound rock to Elton John-esque ballads and a cover of Paul McCartney's Live And Let Die. They'll quickly be followed by a separate EP of eight punk covers, including The Sex Pistols' Black Leather and New Rose by The Damned.

With all the goings-on of the past few years, a little pessimism might have been in order. There were the arrests (in Australia for causing a public offense with their lyrics; in aeroplanes for setting fire to a seat and pissing in the aisle, one a little more accidental than the other; in Axl's Hollywood apartment building for allegedly beating a female neighbour the singer claimed had obsessive fantasies about him). There were the overdoses (when they toured, opening for Aerosmith, the once notorious, but now clean Joe Perry and Steven Tyler handed over the mantle, so to speak, in the form of their custom-made "Toxic Twins" T-shirts). And there were the splits (when Axl failed to show for a gig in Arizona, the band fired him; when the band came on stage in Los Angeles at the Stones show, Axl fired the band; the offenders cleaned up, all except drummer Steven Adler, who spent a year in and out of rehab and was finally, and painfully, fired).Many expected that if a second album came out at all, it might amount to nothing more than 10 or 12 tracks of the same old burnt-out, teenage-decadence fulfilment. Certainly not such a diverse collection of three dozen songs.

In print, it's true, they often seem like just another bunch of attitude assholes with too much attention and too much money for buying drugs with. But that's a misleading impression. Guns N' Roses are the biggest rock'n'roll band in the world at this moment. In some ways it defies explanation - the band, like all great rock bands, has its own internal logic, and all attempts to analyze their appeal as a synthesis of hippy and fascist, sex and anger, fail to explain why it works. It works because it works. Because it looks right, it sounds right and because it behaves right, which is to say wrong.

Despite the posturing of the MTV rock bands, the Tupperware leatherbrats or the fake glamandrogyny that so upset America's parents and preachers and politicians' wives, rock music is the safest it's been in years. Rock's scariest godfathers - Ozzy, Alice, AC/DC, Motley Crue - have publicly declared a preference for Perrier, given up drugs (groupies in LA hang out at AA and Narc Anon these days as much as at the Rainbow) and sleep only with their wives. Rock's new bands, it appears, copy whatever last went platinum and do what their record companies tell them. But Guns N' Roses record company is scared of them; so apparently is everyone else. They're even scared of each other.

There hasn't been anything this wild since punk, and punk never had the same impact in America anyway. No-one ever got on primetime TV and said "fuck" to Barbara Walters like the Sex Pistols did to Bill Grundy. Slash notorious televised "fucks" during Grammies speech were less a provocation than an accident - so "out of his gourd" that he simply talked like he normally did. Guns N' Roses brought us back to the days when Technicolour overdoses, cops in the lobby and doctors at the door in the early hours were part for the course.

Of course the look is dime-a-dozen now, the bandanas and non-designer jeans, kind of Keith Richards, Aerosmith and Suicidal Tendencies squashed together in a car-wreck (watching MTV, Slash once said, was like watching "Axl aerobics") as Guns N' Roses became the latest band to clone.

"It's gone full circle," says Slash. "When we first started was '85, when the music business was just - this big erect monster. It was awful. And we came along and at least we did whatever it was we were doing - something we thought was a blood and tears, rock'n'roll kind of thing - and people dug it. And we sold a lot of records. And we didn't consciously watch it but the record business changed a little bit. And then we spotted, slowly but surely - actually pretty quickly - that it's right back where it was when we started.

"So we've got a new record coming out which is just against the grain as our first one, if not worse." He laughs. "I'm interested to see what effect that has. When our record comes out, I know it's going to be really different - whether it's accepted or not I couldn't give a shit, but it is really very weird because it's like stepping back four years and seeing the music business being in the same place again."

(They recorded so many songs, says bassplayer Duff McKagan, simply because they'd written them, they were good, and the band kept expecting to burn out in the studio but never did. They're releasing them all to wipe the slate clean for the next one. He shrugs off the theory that they did it because there might not be a next one - "that's just rumours; you can say that about any band" - and they're making it two separate albums "because we like to try shit that's never been done" and because double albums are dear and fans can buy one each and tape the other.)

As the sales of their first album shot into the stratosphere, Guns N' Roses became the most talked about band in the world. People magazine was dissecting Axl's marriage while Guitar Player was dissecting Slash's style, observers were passing judgement on their lyrics (ideologically sound one minute, suspect the next) while others were arranging (successfully) for the band to make low-key visits to terminally ill teenagers whose last wish had been to see their idols. Fans wrote moving letters saying how they'd wanted to die until Guns N' Roses spoke to them in their music; a girl fan in Rio sent a note to Duff's hotel room threatening to kill herself if he didn't send an autograph.

A lot of talk, but for the biggest rock'n'roll band in the world - a couple of festivals, the opening slot on tours with everyone from Motley Crue to Iron Maiden and an EP, GN'R:Lies, at the end of '88 aside - not an awful lot of action. Strange to think that this will be their first major headlining tour.

"It's pathetic!" says Slash. "I agree. The band is still scrubbing around, not doing much of anything, and the less we do, the bigger the band gets. It's weird, because we haven't really done anything and we're real recognisable. And we haven't really changed - to this day I still have to borrow cash from somebody because I've never had any money I can spend. I can take a credit card out, but if my girlfriend wants to go shopping I'm like, You don't really need that - that's 90 bucks! You know what I'm saying? That's something I've never adapted to. We haven't changed. We just like to go to a bar, go out, get laid, hang out with whoever's cool. And people treat us so different.

"It's like walking around in Toonville, being a whole human being and walking around with all this shit going on around you. Ridiculous. But I'm used to it. As long as we're working, I'm happy. I dealt with it a lot differently when I was just drugged out. I didn't care. As long as I could get from my connection to home, that was it. But once I was off junk, then everything became crystal clear. I could see all these things going on. It didn't necessarily look better, it just looked more realistic."

So was one of the reasons the album took so long that while one of them "had their shit together", another one was off getting wasted? Or not quite that simple?

"Well, we toured for so fucking long, and by the time the tour was over we were told we were mega - Spinal Tap, you know. You're great! You're great! And we're still walking around trying to make sure you don't have a stain on your jeans after you take a piss kind of thing. And there's all this stuff going on around you, all these people treating you like you're on a pedestal even if you don't feel that way. So we went from nowhere to being this really huge band, not feeling any different, only having people tell you that and react to you a certain way.

"When they dropped us off at the airport after the tour was over, I had nowhere to go. It kind of runs in the family with us - maybe not with Axl but definetly with me - where if I'm not busy and focused, I get loaded to pass the time. So that's what happened. I went through a phase of that and then I cleaned up and we tried to rehearse and we were writing material.

"The worst thing of it, though, was because of no longer having to live in one room, the band got separated, getting their own homes. And that was the hardest part. It's like Slash is here, Axl's here, Izzy's over there, Duff's here, and I don't even know where Steven lives, right? Like, Duff, can we come over? "Well, the gardener's coming today..." That was a whole huge experience that took a really long time for me to adjust to."

Especially since the whole point of being a genuine band is being a gang, and a gang usually hangs out with within spitting distance of the same towerblock.

"Right. If you're in a gang, you don't have one from the Bronx and the other one's from Queens and you meet up in Manhattan. But the bond was still there. I moved into an apartment, the cheapest apartment I could find off of Sunset Boulevard - that's how demented I am, right? - and we just used to party all the time and have amps all about the place and I'd write songs and Duff would come over and every so often Axl would come over and we'd write together. But it was such a long period. And I got so wrapped up in dope and coke and all the fucking scum that goes along with it that finally it just got out of hand. So I cleaned up and bought a house. Then I sat in the house for a while and hated it. I'd lay in bed and stare at the ceiling. There was nothing to do. And then I got back into it and got strung out in a serious way, where everybody was really worried and I had some close run-ins with the police. But then the Stones gigs came around - which I really wanted to do to bring the band back together; that's why after the Stones gigs (and Axl's onstage ultimatum) I went and cleaned up - and then it was Steven's turn."

Only drummer Steven Adler didn't make it out the other end. "We tried our best to get Steven back together," Slash sounds choked. "Steven - he's always been the child of the band, the one that was always just the happy-go-lucky, sex, drugs and rock'n'roll and that's it. He couldn't understand why the drugs were so separated from rock'n'roll all of a sudden; why he couldn't be a junkie and be in a rock'n'roll band, because the twain are supposed to meet on the same ground. But after a while it's really not like that. You have to take care of yourself. People will not go around wiping your ass for you. So a year went by (three visits to rehab) and I finally said, Steven, you've got to go."

It wasn't an easy decision. Steven Adler was the one that got Slash playing guitar in the first place - took him home after high school and played him a Kiss album.

"It still fucks with me. And I still check up on him. I won't go so far as to say he's clean and I won't go so far as to say he's still fucked up. I know he's unhappy. I hadn't seen him since the day it that it was over. Then I was at the Rainbow one night, of all the places to run into him, and I was with Duff and with Matt, who he'd never met... (Drummer Matt Sorum, a sunny and muscular Southern Californian whom Slash admits he stole from The Cult, is Adler's replacement)...It was really awkward. I haven't really seen him since. It's too deep a thing to get into. But the upside of it is that Matt has made the band - I think it was a shot in the arm, no pun intended, that the band didn't necessarily need but that took the band beyond what we were before. I think we're a little bit more - just tight, more focused, more serious about what we're doing. We're not so much the punk band as we were, only because we've been doing it for a while and we're all sort of really aspiring musicians, regardless of the lifestyle. The most important thing I've gotten out of this whole fucking stupid circus that we've been involved in all this time is to sit back and know that we're actually good. And not only that we're good, but that we're original. And if I'm sleeping in a chandelier one night - I stole this from Keith Richards, OK? - I can still get up the next morning and actually play, and play with some sort of integrity, as opposed to hitting one chord as many times as I can as quickly as I can and then continue partying. My playing is my priority, and my playing's actually a lot better. When I listen to the record, it's really good. And that's the thing that's my saving grace and my feelings for the whole thing that happened with Steve."

Apart from the musical element he's added to the band, Matt could come in handy as a referee - as an outsider, not one of the immediate family, he's not so involved in the various family feuds. Notably between Slash and Axl.

"In a way yes, in a way no. He's not part of the real tight-knit family - this isn't the kind of family you just spit into like that - but he fit in really well. Me and Axl are really tight, even with all the stories that you've heard about us. I make an effort, I go out of my way to keep a close relationship with everybody. We're all best friends - you know, you all have those little cliques - but I try and maintain, for any given member. I'm always there for them."

But the best of bands always seem to have a love-hate relationship between the lead guitarist and vocalist - the Stones, Led Zeppelin, Aerosmith...

"If there ever was a combination of fucking opposites, like me and Axl or whoever else in the past, that one is crystal clear. Me and Axl are so unalike that we attract each other.

"The relationship between most lead singers and most lead guitar players is very sensitive, very volatile - I could go on listing these things for hours. It's just very intense. It has major ups and major downs. But somewhere between all this intensity and this friction there's a chemistry. And if the chemistry's right, like me and Axl are really tight, then there's something - a spark or, you know, a need, that holds it together. You fight too. The biggest fights are between me and Axl. But that's also what makes it happen."

Fight about what? Music? Drugs? Who gets the most attention?

"I don't remember us ever fighting over who gets the most attention! No, dumb things. Like a marriage. I hate to harp on that subject because it's so negative and there's so many other cool things about the two of us, everybody else in the band too, that are just more interesting."

What are the "cool" things, then?

"Well, when we talk, we're not band members. We talk about ideas that we have, or remember seeing this or hearing that? We'll just sit up all night and talk, and it's me and Axl talking. It goes beyond anything you could write down. Whatever entity the Slash-Axl combination makes, you can't define it like that. It's just how we are... If I ever gave it that much thought and had an answer, then it would make the whole thing too fucking predictable, wouldn't it?

"The insights to it are really simple: we happen to play well together and we're a fucking band and that's it. It's really not complicated. It's like going to the toilet, you know? Self-analysis is a waste of time."

But it's something most Los Angeles people seem to go in for. Has he been through analysis, for his drinking and drugs or whatever?

"For one, I couldn't see myself going to an analyst because personally I just don't want to know. And the other part being that whole trip of pre-planning your existence is something that people do to a point where it makes life just not fun anymore, because you are trying to preconceive your next move, and so on and so forth.

"If you were to ask, as a therapist, Why do I drink? - the simple thing is you do it out of boredom and to relax. The worst thing is it's for people who are so volatile and so shy - because that was always my biggest problem, to be able to deal with everything that's going on, especially when you're in the public eye so much and then being a very reserved kind of person. You end up drinking a lot to come out of your shell. In that way it's a vicious sort of drug, because it works."

Coke?

"Well that's obnoxious, and you can't get it up! And you get into these really ridiculously bitter fights. And then, when you do a lot of coke, you tend to drink a lot - and I know that one real well too!".

Heroin?

"I just liked it. I liked the way it felt. And fuck, I didn't know if I did it four or five days in a row I'd get fucking hooked on it! And that's a different subject altogether. That drug takes you over mentally and physically, so much that to come back is hard. I was never a big coke addict, ever. I had not so much a drinking problem as to just want to drink and get rowdy. I used to love to get just fucking drunk! I used it to escape a bad day. Sometimes, I'd much rather just go home, sit down with a glass or something and kick back and go to sleep. I really don't feel that I have the intense addiction that people believe.

"I was forced into rehab once when I was going through a very big needle phase. Three days. And I saw what that was all about, and looked in the Yellow Pages and got a car and got myself out of there. I said, I'm not this fucked up! I mean, I know when I'm doing something."

Do you write best when you're high?

"No, but I wrote some really cool shit when I was high. There's a song called Coma, a long song, really heavy, and I wrote that loaded. And it's not something that I can really see myself writing right now. And then me and Izzy wrote a song called Dust And Bones in a similar kind of state. But whatever you're going through, your material is supposed to be some sort of mirror of your experience. There's so many bands now who write stuff that doesn't relate to anything."

Is he happier now than when the band first started and were all living in one room?

"I'm about to be. As soon as we leave. I wanted to get on the road the day we got off the road. I'm a complete road dog. I hate being attached - and I have so many animals home, too. It's strange..."

There's 21 snakes, two dogs, 10 cats. The snakes don't eat the cats, but there was a near miss when Slash and two friends had to save one suicidal feline.

"She's got this deathwish, though. She still - even the same day - stands against the glass cage with her paws up. I'll probably come home off tour and find a cat with two front legs and a tail!"

Between albums the band found time to make their movie debut in the last Dirty Harry film. "Clint Eastwood! One of the most intimidating people I've met. You'll have to try and picture this: we're on location in a graveyard, all these people and then this funny looking rock band, totally out of place. And in between takes this nine-foot character comes over and goes, Uh, nice record, and walked away. And that was it. I bet he never heard it and they're obliged. But he was more Clint in person than he is on the screen. He seemed nice."

They've worked with Alice Cooper - "a sweetheart" - and he's returned the favour by singing on their album. Slash did some stuff with Lenny Kravitz. They went to high school together. "We didn't know each other then. I was in what you call Continuation School, which was for kids who smoked in class, that whole thing. But we recognised each other, jammed one night... He's a real cool character."

Slash worked with Iggy Pop. "I've known him since I was little. My mum went out with David Bowie when I was little (Ola Hudson designed the outfits for The Man Who Fell To Earth). Iggy was in a mental hospital when I first met him and so my mum and I and David went to visit. He's such a fragile, sweet, soulful, honest and sincere guy. I really love him a lot. That was great. We did that in one day and it kicked ass."

And the he worked with Bob Dylan.

"That was a drag. I really regret that. I'd just finished the Iggy Pop thing and Don Was approached me. I grew up with Bob Dylan stuff, but Bob Dylan then is not the same as Bob Dylan now, and I hadn't really paid much attention to him. But I said OK. I went to the studio and I met George Harrison, and he was great. He was playing when I wasn't there, this gorgeous slide guitar, and then I met Kim Basinger who could have done anything! Anyway, I finally met this little guy who looked like an Eskimo. It was a summer day and he's wearing a heavy wool sweater with a hood over it and a baseball cap underneath the hood and big leather gloves on and appeared to be stoned out of his mind. And he was really just impolite. I didn't have a good time at all. I was being as outwardly nice as possible, just trying to finish the guitar part, and I did one of the best one-offs that I can remember doing. And everybody was happy and I left and the record was about done. And then at last minute he took my guitar solo off because he said it sounded like Guns N' Roses."

And then he worked with Michael Jackson.

"I didn't meet him. I regret having done that too, only because that's way too automated for my taste. The guy books the studio for like two or three years and comes in once every sixth months. I was very still. I'd do a riff and it was really cool and they'd sample it for the rest of the song. You know, where I come from is like what they call the Old School - you get in there and you play. I think Michael Jackson is great, but not the process."

Talking of Old School, how did he get along with the Stones?

"I never met them. The reason I didn't meet the Stones, one was that I was high out of my gourd - that was during my real wasted days, and basically when you are high like that you don't care who it was; nothing was more important that getting on with what I had to get on with. The other thing was to meet the Stones - there was so much like putting Guns N' Roses up against the Stones, and every time you would be in the same room there would be 50 paparazzi guys taking pictures: Slash and Keith Richards, that whole big generation rock band bad boys bullshit. Basically I wanted to meet them on a more personable level, so I never made any efforts to meet them at all, and when the band did a photo with them I just didn't show up.

"But you know who I met? I'm standing watching Living Colour at the Stones gig on the side of the stage and this character walks up to me and introduces himself and says, "Hi, I'm Little Richard." And I froze! It blew my mind for one thing, for him to even know who I was, and just to meet this guy in general.

"It's great. I'm 25 and I've met everybody."

Slash is the band's only member to have been born into a rock'n'roll family. He was "fortunate", he reckons, "to have been exposed to so much overindulgent, egotistical, just basically ridiculous rock'n'roll environment.

"I watched all these things go down. I watched people go down. I watched a lot of heavy shit go down and I learned a lot from it.

"Because I've always been one to try and be very aware of what's going on around me. And all the fuck-ups I've made I knew I was making, and I just happened not to care. But once I got to a certain point where - you know when you're standing at the edge of a precipice, which way are you going to go? And I just sort of opted for the smarter side. So I'm still here at this point. Also, if I was going to die, it would have to be because the stage collapsed or a lightning truss fell on me or something! I'd hate to go out because of selfpity."