The nineties, says Edge, was about taking 'the idea of a rock 'n' roll band, abstracting it as far as you possibly could - and then reconstructing it again.'

'U2 was as big as any other rock band in the world as the '80s turned into the '90s, writes Gary Graff of United Press International. 'Rolling Stone magazine had even dubbed it "The Band of the Decade."

"U2: The Best of 1990-2000," which hits stores Nov. 5, chronicles what happened during the next 10 years - much of which came as a surprise to the Irish band's fans.

"It's really the story of us taking the idea of a rock 'n' roll band and abstracting it as far as you possibly could - and then reconstructing it again," explains U2 guitarist The Edge by telephone from Dublin.

"I think that's really, in a nutshell, what we did during that period. At every turn, it was an attempt to find inspiring places to go as songwriters and artists."

That was no modest endeavor. Founded during the late '70s in Dublin by The Edge and his band mates - front man Bono, bassist Adam Clayton and drummer Larry Mullen, Jr. - U2 took inspiration from punk rock and channeled it into an anthemic, inventive and direct approach that drove lyrics of conscience borne from the band's strong Christian devotion.

The group dubbed its sound "three chords and the truth," and it clicked. By 1987's "The Joshua Tree" U2 was on the cover of Time magazine and on top of the charts both with albums and hits such as "Pride (In the Name of Love)," "With or Without You" and "I Still Haven't Found What I'm Looking For."

"I think we all had a strong sense that we wanted to communicate, that we wanted to connect with our audience," The Edge says.

But by the time U2 rolled out "Rattle and Hum," its 1988 documentary filmed during the tour to support "The Joshua Tree" album, the group was ready to close the door on an era and hungered for something new. And different.

"We began to loathe who we were," Bono acknowledges. "We had a lot of kind of moral baggage that we were carrying and that people handed to us; I certainly felt like I couldn't live up to the songs, and that I didn't have to.

"Somebody described 'Achtung Baby' as the sound of four men chopping down 'The Joshua Tree.' I thought that was true."

Over its three '90s albums - "Achtung Baby," "Zooropa" and "Pop" - and a collaboration with Brian Eno called "Original Soundtrack I," U2 pursued a more avant-garde rock path, experimenting with industrial and electronic approaches and lacing humor and irony into its earnest lyricism. The once bare-bone stage shows became prop-laden spectacles, and Bono began to adopt a series of characters.

There were still strong record sales and hit singles. But there was also some confusion about what U2 was up to.

"We turned on ourself, in a way," Bono explains, "having fun with some of the ideas of ego that we were playing with. And we managed to give ourselves a bit of freedom, a bit of room to breath."

That process ultimately yielded 2000's "All That You Can't Leave Behind," a multi-platinum, multi-Grammy winning triumph that was hailed as a return to form even though U2 continued to incorporate some of what it had embraced during the '90s and found some new sonic terrain of its own to explore.

"It was very inspiring to kind of strip it back," The Edge says, "and go into the rehearsal room and discover it was still inspiring to work together in a very simple way, where the chemistry of the musicians playing together was really the glue, and the idea behind the sessions and the songs came out of simply playing together."

The 16-track "The Best of U2 1990-2000" chronicles the entire period, while a DVD of videos from that time is due out on Dec. 3. CBS, meanwhile, is planning a late-November broadcast of a U2 concert held during the summer of 2001 at Ireland's Slane Castle.

The project also hearkens to the future with two new tracks - "Electrical Storm," a lushly impressionistic piece co-produced by British electronic pioneer William Orbit, and "The Hands That Built America," which was commissioned by film director Martin Scorsese for his forthcoming epic "The Gangs of New York."

With those tracks in hand, meanwhile, U2 is eyeballing its next studio album. Bono continues to travel the globe as part of his continuing campaign for Third World debt relief, but he and the rest of the group are working on ideas - individually for the time being, though The Edge guesses it won't be long before work on it begins in earnest.

"We'll regroup probably at the end of the year and start trying some things out," he says. "Right now my instinct is to make a very raw kind of guitar-bass-drums, an album with a lot of attitude and a lot of that kind of life force, the vitality I association with guitar bands in full flight.

"That's the way I'm approaching the music initially. But as often happens with U2 albums, you start out with one intention and at a certain point you start to get carried by the music itself, and it can take you somewhere completely different."