Metallica created a decibel-laden wall of sound that had the power to shut the world out. Their music stirred up the disillusioned and bored as much as the angry and alienated.
So successful were they - album sales exceeded 50 million - they redefined the genre. People who thought it a crass art-form were forced to think again.
In recent years they have done some truly shocking things. First they cut their hair. Even scarier, they're veering off the road of excess in favour of a palace of contentment and wisdom.
James Hetfield, guitarist and lyricist, was always the one who instilled fear. "Boo," he barks at the mention of it. Grim and unsmiling on stage, his menace captivates adoring girls. Slim and tanned, sat at a bar in an unprepossessing rehearsal studio near San Francisco where the band is based, he does not take the adoration seriously. Anyway, he is married and enjoying it. His wife, Francesca, born in Argentina, is expecting their first child in early spring.
"Our household is very 50/50. I think we all should be treated equally. She doesn't belong in the kitchen, barefoot, pregnant. I don't belong in the garage fixing the cars. That's where I like going and that's what she likes doing, but it's not a forced thing."
His wife, coming from a macho family where men demand their dinner on the table, is adapting to her newish man. "I can't respect a woman who will take that," says Hetfield. "I like a woman who's got some balls, some strength. As long as I can beat her at arm-wrestling, that's fine."
Hetfield loves the macho life. He's just come back from an elk hunt in Colorado with friends. He remembers the shock and wonder of killing his first animal, a rabbit.
"I feel there's this animal part of me that I can identify with. I feel good going out, pushing myself physically and mentally, being out there away from everything. Stalking, outwitting the animal, harvesting this animal and having it in my freezer in the winter and eating it with my friends, it's great."
This year has seen dramatic changes for Hetfield as he settles into family life. "I like a home-cooked meal, yeh, I do. I want to create a family and make it work. I believe in family values."
He collects memorabilia of the Wild West and though he says he admires some of the policies of conservative politicians he hates their stiffness and would like to be free of laws that stop him driving a car at 200mph. His controversial song "Don't Tread On Me" was inspired by the Culpepper Minutemen of the Revolutionary War. It was a patriotic warning to fundamentalists not to mess with America.
But Hetfield is too sophisticated a character to be pigeonholed as a Commie-hating xenophobe. Most of his songs and much of his rage is directed at an upbringing where rules were forced on him through his parents' devout belief in the "culty" Christian Science faith. The wrenching effect of his parents' separation when he was 10 years old and their deaths from illness has all added to the need for an outlet for his frustration and pain.
Metallica became his family, and Lars Ulrich, the Danish-born drummer, co-founder of the band and co-songwriter, his "brother'. Ulrich has also recently married. His wife, Skylar, has just graduated as a doctor, and they too are planning a family. Once it was taboo in the band to bring a "chick" along because that would have inhibited everyone's fun. Now the prospect of an on-the-road creche is a distinct possibility.
Ulrich is surprised at my direct question asking him if he still takes cocaine. He does, "recreationally". He goes on cocaine and booze benders, he says, after gaps of abstinence lasting many months. Hetfield, though a drinker, says he has never tried cocaine.
"The difference between asking me about drugs now and five years ago is that then I would have said no," says Ulrich. "And that was because I was a lot more insecure about myself back then. I'm certainly no angel, but I am secure enough to recognise my shortcomings. I can't lie about those things any more.
"I don't want to be a role model and I don't advocate any type of drug abuse, but I don't advocate lying, either," he says.
Ulrich, voluble, intense, serious, short-haired, says he is bored with rock culture. He is more enthusiastic talking about his art collection. He owns some of the most important pieces from the grouping of post-war self-taught, naive painters and poets from Copenhagen, Brussels and Amsterdam, known as the Cobra Movement.
Ulrich was responsible for choosing the abstract cover of the previous Metallica album, Load, by the photographer Andres Serrano. It is from a series called Blood and Semen. The new album, Reload, continues the theme; this time it is Blood and Piss.
Metallica have survived and blossomed because they seek change and distance from hard-rock stereotypes. As Hetfield says, "Here's what I've made of myself, look what can happen. I'm not going to live in darkness for ever. Why? Change, we've really discovered how cool it is." And this from a man whose first album was called Kill 'Em All. In contrast, on the new album there are songs like "Unforgiven II", about not living your life for others and taking responsibility.
Hetfield admits, "Music is our therapy. But I think we're still as angry and confused as we were."
Ulrich, too, after years of substance oblivion and chasing girls aimlessly, is on the self-realisation road. He controls the band's business affairs and is trying to relent from his control-freak obsession. "I am trying to take a step backwards and not be so controlling and demanding on everybody else. I am trying to make myself a better person and not be so on top of everybody else."
After a previous failed marriage, three long-term relationships and a tally of 200 female "liaisons" in the band's first five years, Ulrich has stopped his roaming, thanks to Skylar. "For the first time in my life, I found something else that motivated me outside of the band. I'd never been in a relationship with my best friend and I'd never been in a relationship with a person that I'd rather spend all my time with than running all over the world on tour."
Ulrich used to live for touring, finding the recording process a painful if necessary inconvenience. It also helps having a wife who is a motivated professional, equally dedicated to her own career, and who knows that her professional life as a doctor must be separated from her private life if sanity is to be preserved.
After all this self-realisation, you might expect Reload to be full of ballads. There are one or two. There is also more of a melodic feel to it. It is a mature record, superior to their previous effort, and still with that velocity thrust of teeth-gritting rage.
There seems to be plenty of creative steam left in them. Ulrich says he will know when it is time to leave the band. "Not that I welcome it, but I know that when the moment arrives, when it's not fun any more I know I will recognise it and I will walk away."
`Reload' is released by Mercury Records on 17 November.