You can't overthink the music. Mood and intensity can't be manufactured. The blues isn't about structure; it's what you bring to it. The spontaneity of capturing a specific moment is what drives it.

That's the music that I play at home all the time, Joni Mitchell. Court and Spark I love because I'd always hoped that she'd work with a band. But the main thing with Joni is that she's able to look at something that's happened to her, draw back and crystallize the whole situation, then write about it. She brings tears to my eyes, what more can I say? It's bloody eerie. I can relate so much to what she says. "Now old friends are acting strange/They shake their heads/They say I've changed."

Right from the first time we went to America in 1968, Led Zeppelin was a word-of-mouth thing. You can't really compare it to how it is today.

The key to Zeppelin's longevity has been change.

We went in and recorded exactly where we were at that point in time. I think because of the quality of musicianship of the band has given it the longevity. I thought the music would endure, I didn't think I would ... I always thought I'd be dead by 30, then dead by 40 and on and on. Now I'm 55 so I didn't even die at 50.

There is far more sensitivity in acoustic guitar players than could ever be compared to any synthesizer. That's a personal point of view but that's the way I see it. I think that's what it's all about. The drive, the fire, the passion - it all comes out on the guitar.

It's interesting when something new comes along, a band of dwarfs playing electronic harps or something, but I'm not searching.