'It started out to be a rock 'n' roll album, pure and simple. We were very excited that Edge wasn't sitting at the piano or twiddling a piece of technology, because he is one of the great guitarists.

Halfway through, we got bored, because it turns out you can only go so far with rifferama. We wanted more dimension.

Now you've got punk rock starting points that go through Phil Spectorland, turn right at Tim Buckley, end up in alleyways and open onto other vistas and cityscapes and rooftops and skies.

It's songwriting by accident, by a punk band that wants to play Bach...'

Bono about U2's eleventh album, 2004's How to Dismantle an Atomic Bomb.