You can't buy time. Everything, for me, seems to be a race against time. Especially musically.

There's a certain standard in classical music that allows the application of the term "genius," but you're treading on thin ice if you start applying it to rock & rollers.

I don't know whether I'll reach 40. I don't know whether I'll reach 35. I can't be sure about that. I am bloody serious. I am very, very serious. I didn't think I'd make 30.

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.

You can't expect to be the same person you were three years ago. Some people expect you to be and can't come to terms with the fact that if a year has elapsed between LPs, that means one year's worth of changes. The material consequently is affected by that, the lyrics are affected by that... the music too.

There's so many different styles and facets of the 360-degree musical sphere to listen to. From tribal to classical music, it's all there. If the bottom was to sag out of that, for God's sake, help us all.

Many people think of me as just a riff guitarist, but I think of myself in broader terms. As a musician I think my greatest achievement has been to create unexpected melodies and harmonies within a rock and roll framework. And as a producer I would like to be remembered as someone who was able to sustain a band of unquestionable individual talent, and push it to the forefront during its working career. I think I really captured the best of our output, growth, change and maturity on tape - the multifaceted gem that is Led Zeppelin.