DUBLIN -- It's been a good year for U2, to say the least.

In its ninth year, the Irish quartet scored its first American No. 1 singles with "With or Without You" and "I Still Haven't Found What I'm Looking For." U2's fifth studio album, "The Joshua Tree," spent nine weeks at the top of the charts and has been selling in quantities the band could scarcely have dreamed of a few years back. Its videos, including the new "Where the Streets Have No Name" (a live performance shot -- until the police shut it down -- on a Los Angeles rooftop), are in heavy rotation on the nation's video programs.

Last spring U2 completed the first leg of a spectacularly successful American tour, playing to 457,000 people in 29 dates, before spending the summer months filling stadiums all over Europe. Seldom has a dyed-in-the-wool rock 'n' roll band fired the public imagination to this degree, with tickets changinghands at up to 10 times their face value.

Now U2 has embarked on the second leg of its American tour, playing a mix of arenas and stadiums: There will be 46 dates and 1,527,000 fans this time. Today the group is at RFK Stadium, where 45,000 tickets were sold in one hour.

They remain familiar figures on the Dublin landscape, etched in familiar cameos: bass player Adam Clayton drinking across from you in a nightclub, drummer Larry Mullen slipping into the shadows to view some unknown local band, the Edge (U2's guitarist, born Dave Evans), shopping with his pregnant wife, or singer and songwriter Bono Hewson (known simply as Bono) swapping tall tales with an elderly working man in his local bar.

Unlike earlier generations of Irish artists, they have resolutely refused to decamp to London, Paris or New York. Perhaps that's why Irish fans have yet to fully come to terms with the special nature of U2's appeal -- or with the dawning realization that the torch has been passed to it as the lone remaining band of its generation to breathe new life into old rock ceremonies and revive abandoned dreams. It's much easier to call across the bar and ask Adam to pass the cigarettes.

To be sure, their lives in Dublin are a lot less private than they used to be. It's not unusual to find U2 fans from all over the world camping outside favorite pubs and, sometimes, outside their homes. Yet even that intrusion can turn into illumination.

"I don't know how this will sound," says Bono, "but there was this one girl in the bushes. She was Italian, 18, very beautiful, sitting there in the flowers. And she said, 'I just wanted to come to Dublin and meet U2 before I die.' And I thought, 'They always come up with a good angle but this really is a good one.' I didn't know whether to laugh, just in case. So I talked to her, didn't take it too seriously and went off.

"But the next day, two BMWs came along and out came these Italian men in designer suits with flowers and flowers, presenting them to me because we had looked after this man's daughter who had some incurable illness. And that was almost shocking. How could I live up to that responsibility? I just can't come to terms with that.

"The bottom line is that music means a lot but what they haven't separated is the music from the musician. Because the musicians are only ordinary people. It's the music which is extraordinary, if you like."

Once, writing about the United States, Bono was pained about being a "Stranger in a Strange Land," but these days U2's members are familiar figures there. And their new familiarity with America provides much of the focus for the sometimes tempestuous "Joshua Tree." While a song like "Red Hill Mining Town" is specifically about the trials and tribulations visited on working-class people in the British miners' strike, the album as a whole represents the American side of U2's collective personality.

Lyrically, "The Joshua Tree" makes an ethical and emotional journey across many different Americas. It's not a comfortable album in any respect: It traverses landscapes littered with human debris without flinching; it etches the pain and suffering we inflict on one another.

Previous British rock tourists have made albums of their American sketchbooks, but this one is different. There's an unmistakable Irish tinge on "The Joshua Tree" that frees it of the condescension and detachment that so often characterizes the British rock perspective. At bottom, with U2, is a feeling of empathy and respect -- not for American institutions but for the people of a vast and many-faceted continent.

"I really believe in America. I really believe in Americans, I should say," Bono notes. "I think they're a very open people. It's their openness that leads them to trust a man as dangerous as Ronald Reagan. They want to believe he's a good guy. They want to believe that he's in the cavalry, coming to rescue America's reputation after the '70s. But he was only an actor. It was only a movie ...

"Insofar as we are Irishmen, on one level we have no duty to speak out against America or bite the hand that feeds us, as they would say," he adds. "And I think we have bitten the hand that feeds us, but we do so from a position that, as I say, we have belief in Americans ... It's still a thrill to be there. I mean, America is the promised land for a lot of Irish people.

"I'm really stuck with my memory of our first trip to the U.S. We were just so wide-eyed. We really embraced America and indeed America embraced us. And over the last few years we've had to reevaluate our impressions of America, because of the fact that we walk onto a stage every night. When we're in America playing to 20,000 people, we have to ask ourselves the question: What can rock 'n' roll music do? Go 'round in circles? I think on {"The Joshua Tree"} there are questions asked, if not answered, about America."

"Awkward questions," adds the Edge.

Released last spring against the sordid backdrop of Irangate, "The Joshua Tree" is about articulating the sense of outrage that America's unique combination of arrogance and apathy inspires from an Irish perspective. But it is about more than that. In a world where power is abused on a colossal scale, U2 sought and found the ultimate symbol of triumph over adversity. "The Joshua Tree," named after a species that blooms in the southwestern desert, is about the belief that you cannot kill the human spirit -- the belief that in spite of the arid wasteland of contemporary power politics, something beautiful and enduring can be forged out of human commitment and idealism in action.

Says the Edge: "There's the America of Ronald Reagan but there's also the America of Bobby Kennedy, of Abraham Lincoln and George Washington."

Right from its earliest dates in Dublin in 1978, U2 radiated a sense of vision.

"Everybody has a spiritual awareness," Bono said back in 1979, "but in rock music it tends to be forgotten. We're determined to achieve a position where we have artistic freedom and where we can affect people the way we want to affect them." Then 19, he was setting the terms for the band's creative growth even before U2 had signed an international recording deal.

As teen-agers picking up instruments for the first time, U2 was no more or no less proficient than a whole generation of other absolute beginners. But there was a chemistry there. Bono recalls the band's first gig, in its pre-U2 incarnation as Feedback, with relish. "We walked up on stage; I was playing guitar, and when I heard that D chord, I got some kick. ... That was a very special concert; that was one of the best concerts of our lives. It was like four blind kids blustering away and there was evidence of just a little light in the corner and we started to work towards that. We built ourselves around that spark."

Dublin audiences, notoriously cynical about their own, found it impossible to resist that spark, which would eventually grow into the unforgettable fire of U2's live performances. Before it had released an album, U2 had built up locally the kind of intensely loyal following for which it has since become globally identified.

U2 gave young Dublin fans something to believe in, a voice that articulated their confusion, their anger, their aspirations -- and finally the optimism they refused to relinquish in spite of troubled times. With the institutions on which they had been taught to depend failing all around them, a significant portion of Irish youth discovered that U2 -- with its songs of faith, hope, love, celebration and commitment -- filled the void better than anything else.

Yet in late 1980, when the band released its debut album, "Boy," many simply lumped U2 in with such Liverpool groups as the Teardrop Explodes and Echo and the Bunnymen as part of that year's neo-psychedelic movement. Later, after its third album, "War," it was slotted beside fellow-Celts Simple Minds, Big Country, the Alarm and the more willful Waterboys, as crusaders for an anthemic "Big Music."

By "War," the album with which it first broke through to a wider audience in the United States, U2 had developed an unmistakable sound. The band's spiritually inclined lyrical preoccupations had won it an audience. Yet back in Dublin after the "War" tour, Bono spoke about the end of U2. The band that had made those first three albums was finished. The lineup would not change -- but for the next album, there would be a new U2.

With age and experience, Bono had learned that the primary colors deployed with such stunning effect in the early years were no longer enough to convey the band's increasingly complex relationship with the world. Simple rallying cries no longer seemed enough.

The result was an album of far greater subtlety, "The Unforgettable Fire," produced by Brian Eno and released late in 1984. Vastly different from anything the band had done before, it revealed a poetic quality previously only hinted at. The musical textures were deeper, more resonant -- an autumnal glow beside "War's" bold summer red. In sales, it outstripped "War" -- but Bono remained restless. He was unhappy about the impressionistic lyrics of the majority of the songs.

After the band's first sellout Madison Square Garden gig in 1985, Bono spoke about his desire to write songs that could be played on radios all around the world -- "songs that window cleaners hum, songs that people listen to in traffic jams." The band's tribute to Martin Luther King, "Pride (in the Name of Love)," looked in that direction but it was only a start.

"Most of the songwriting I've done has been more prose than song," Bono concluded then. "I feel I must begin to come to terms with being a songwriter."

"The Joshua Tree" is a further shift in the pattern. Bono has jokingly cast himself as the "American" of U2 and the Edge as the "European," but though such polarities may be artificial in this tightly knit group, the album's musical and lyrical preoccupations with so many conflicting American ways contrast vastly with its more impressionistic predecessor.

It is both the most ambitious U2 album and the most troubled. With a new emphasis on the poetic power of language, it relies less on faith, and is less buoyant in its celebration. Rather, "The Joshua Tree" asks questions of itself and of its audience that might not have seemed within the band's scope until recently.

"As with much U2 work," says the Edge, "it's 'reactionary' in a sense. Whereas 'War' was a reaction to the weak, placid music we saw everywhere, I think this was, in a funny way, our reaction to 'The Unforgettable Fire.' We had experimented a lot in its making and done quite revolutionary things for us, like 'Elvis Presley and America' and '4th of July.' We felt on this record that maybe options were not such a good thing, that limitation might be very positive. So we decided to work within the limitations of the song as a starting point. 'Let's actually write songs.' We just wanted to leave the record less vague, open-ended, atmospheric and impressionistic. Make it more straightforward, focused and concise.

"I used to think that writing words was old-fashioned, so I sketched," Bono explains. "I wrote words on the microphone. For 'The Joshua Tree,' I felt the time had come to write words that meant something, out of my experience."

The album's bleakness, he says, might be considered "forbidden ground for U2 because we're the 'optimistic' group. But to be an optimist, you mustn't be blind or dead to the world around you. If I can be objective, and of course I can't, the album's real strength is that though you travel through deep tunnels and bleak landscapes, there's a joy at the heart of it."

Sometimes Bono sounds like the John Lennon of "Revolution." Rather than traditional political activism, he says, "I suppose I'm more interested in what you might call a revolution of love. I believe that if you want to start a revolution, you better start a revolution in your own home and your own way of thinking and of relating to the men and women around you. I'm trying to come to terms with global ideas like Live Aid, Artists Against Apartheid, Amnesty International and the 'Conspiracy of Hope' tour. These ideas are great ideas. We believe in and belong to them yet, for me, the future lies in small-scale activity. For instance, commitment to a community, like U2 are committed to Dublin, commitment to the people in your place of work, commitment to relationships and the ones you love."

When you come down to it, he adds, "I don't think it's up to bands to have their politics and point of view worked out. I don't think it's up to me as a singer to have answers. I just think it's important that you put questions. I don't know of a rock 'n' roll band that ever offered up answers and I think it's wrong for pop stars to be politicians. I like the idea of Jim Morrison, who called the Doors 'erotic politicians.' I thought that was kind of funny. Because you're put in a position where, because you have made music that means something to people, your politics or point of view is given far too much importance.

"What comes to mind is Elvis Presley, who meets with Nixon and he's made an antidrug marshal -- and the man is loaded, out of his brains, with the badge on. I've said it before: Elvis Presley's genius was the way he held the microphone, the way he sang into it.