U2's headquarters lie inside a drab warehouse on a narrow street along Dublin's Hanover Quay basin, totally anonymous save for the thousands of U2-related graffiti scrawlings that span the block. Among the gems sprinkled amid the lyrics and doodles and marriage proposals: U2 ROCK, SEX PISTOLS ARE BETTER, THANKS FOR KEEPING ALIVE OUR DREAMS, BONO IS A FRAUD. And, of course, they're all true. Because U2 didn't become U2 without a fair helping of messy contradiction and unsolicited sloganeering.

The mere fact that an outfit of this stature has been able to operate freely in plain sight at this address for 15 years, without notable bother or visible security, probably says more about Dublin than it does about the import of the goings-on behind the double-wide steel doors. Because the band's import -- not as firebrands or as reliably bankable anthem-merchants, but as a cultural entity whose mere continued existence, much less relevance, belies history and common sense -- can, at this late date, scarcely be overstated.
Watch: On the set with U2

Upstairs in the modest reception area of "the studio," as its owners simply call the compound, there are no distinguishing markers hinting at who those owners might be -- no posters, photos, or platinum records. Just four plastic mailboxes mounted behind a desk, each labeled neatly and in need of emptying: BONO, EDGE, LARRY, ADAM.

For a group whose identity relies so heavily on an unlikely collusion of demagoguery and just-folksiness, and whose wealth and influence have long since passed wildest-dreams territory, the simple notion of why U2 must be an ongoing concern is one its members seem to have spent little energy deconstructing, or even questioning. To say it's for the love of the music, while no doubt true, just feels too pat. Of every rock band ever to exist -- music lovers all, presumably -- not one has approached U2's consistently upward 33-year career trajectory. (Yes, Mr. Martin, we see your hand -- we'll check back in 2031.) Credit the elusive alchemy of mass adoration, critical respect, and no one dying, all while the music industry collapses beneath its perch. The facts don't lie: 145 million albums and counting sold worldwide, and a reported 12-year, $100 million touring and merchandising deal with Live Nation. What U2 have done, and what they continue to do at a surprisingly hungry pace, has left the realm of statistical anomaly and entered that of minor miracle.

"Fear of being crap is a great motivator," says Bono, 48, holding court, as each member of U2 will, in the downstairs lounge, an unassuming room with mismatched sofas and a biography of Thin Lizzy's Phil Lynott on the coffee table. Glass doors open up on to the harbor, where an ancient, rusty tugboat sits anchored, scenery as cautionary metaphor. The easiest way to avoid being crap should be to not even tempt it, to settle into luxurious geezerdom, maybe reunite every decade or so for a tossed-off record and a behemoth tour to keep the tax-shelter estates in foie gras. "To miss realizing the potential of what a band like U2 can achieve in various different spheres, to me," the singer says, "is betrayal."