I like change and I like contrast.

We kept moving forward and didn't try to recreate the past .. the approach to each album was radically different every time. Many bands would have some success and, because they were locked into having a single - something we didn't have to worry about - they had to make sure there was something similar on the next album ... that was never the idea with Led Zeppelin .. the goal was to keep that spark of spontaneity at all times.

There was no working title for the album. The record-jacket designer said `When I think of the group, I always think of power and force. There's a definite presence there.' That was it. He wanted to call it `Obelisk'. To me, it was more important what was behind the obelisk. The cover is very tongue-in-cheek, to be quite honest. Sort of a joke on 2001. I think it's quite amusing.

I'm obsessed - not just interested, obsessed - with folk music, street music, the parallels between a country's street music and its so-called classical and intellectual music, the way certain scales have travelled right across the globe. All this ethnological and musical interaction fascinates me. Have you heard any trance music? That's the thing.

I don't like to tell people what format they can get things in, or say, "I'm only going to release this on vinyl and nothing else. You have to come to my world." I don't like to say that to people either. But, I do think there's a loss of romance.

I'm not a guitarist as far as a technician goes, I just pick it up and play it. Technique doesn't come into it.

(The Song Remains The Same) is not a great film, but there's no point in making excuses. It's just a reasonably honest statement of where we were at that particular time. It's very difficult for me to watch it now, but I'd like to see it in a year's time just to see how it stands up.