On a personal level, he is separated from his wife, Aishlinn, with whom he has two daughters, and he now has another son and daughter with his current partner, an American dancer.
Close on 100 million albums having been sold since they formed in 1976, U2 remain the biggest rock band in the world. For most of their tenure, with a few exceptions, they have matched commercial success with critical acclaim. It's been a funny old rock 'n' roll world for The Edge, who was given a year by his parents on leaving school to "make it" before getting a "real" job. The man who was going to be a civil engineer is now part of one of the music world's best-known songwriting teams, and his guitar style is distinctive enough to warrant its own adjective in guitar textbooks.
So as for fortune and as for fame? "The really great thing about this country," he says, "is that no matter how well-known you are, you can't be more famous than Gay Byrne. I can walk around pretty much and not be hassled, there's just certain places and certain times of the day you have to avoid. To be honest, though, the most you'd get is people waving at you or saying hello, and that's very welcome. There's a limit to the impact of celebrity in Ireland; people just can't be bothered. What we all find is that it's much worse abroad - Italy's a bit mad and so is the US."
Many people thought that he would have been driven out by now: "Not at all, it's never got that bad. The temptation may have been there years ago to move to the US because over there they have such a love of success, so that would have meant piles of money and piles of love just for being successful. But since we can all remember, we've always treated Ireland and Dublin as a haven away from the rock 'n' roll madness that happens elsewhere. This is our land of reality but also in a very significant way, this place is so important for our work, for our songs. We have a connection here, with the streets, with friends. What you have to remember also is that U2 were first inspired by punk rock and that meant having a great distrust of dinosaur rock groups - you know the whole thing of going off and buying your own fish farm. We've carried that distrust with us and what stops us going down the `fish farm' route is a fear of losing our connection with our culture, losing those vital points of reference.
"We're also lucky in that all of this didn't happen overnight to us, the way it has happened with other bands. And when you're in a four-person group, no one ego can run riot because the three others will be very quick, very quick indeed, to point out the error of someone's ways."
Does he think he gets off lightly in terms of media/celebrity scrutiny because Bono just seems to attract/absorb most of the attention? "First of all, I would hope that we are seen as being successful because of the work we do and not just famous for being famous. You've got to be careful how you walk that line. Quite seriously, I didn't join a band in order to become a celebrity; I really did do it for the music. As for living in Bono's shadow, I don't think so. You know, some people are more extrovert than others and more comfortable in the limelight - it's as simple as that really. We never sat down in this band and planned that there would be one member who everyone reads about in the paper and another one who is quiet and just works away on the music. With press reports, yes, I do get pissed off sometimes when people take pot-shots at you or intrude into personal matters. It's hard to know how to react sometimes. You do come to the realisation that the media is a business, there to sell papers. To be fair, though, we've never cultivated any cult of personality. I mean we wouldn't do Hello! or anything like that."
Coming back into a pop-dominated music world, will U2 really be the saviours of rock music, as one recent headline had it? "Guitar rock music is not in great shape at the moment - the last band to really do it for me in that regard was Oasis. I just don't think it's enough these days to have a jangly guitar sound, a few good tunes. Don't get me wrong - I'm really into pure melodic music, all that early Beatles stuff I love, but I wouldn't be such a huge fan of, say, Travis. A band like Coldplay are a bit more interesting, but still I think all the imagination and innovative energy out there is going into pop music. Rock music needs a lot more creative ambition. Radiohead's Kid A? - I really like it."
And on that bombshell, we let The Edge get on with his packing for that afternoon's promo trip to Paris. He's got all that he can't leave behind: "That's right, a washbag and an extra pair of socks".
U2's All That You Can Leave Behind album is released on the Island/Universal label on October 30th.