"Raw blues. This is from the 1920s but sounds contemporary. When I was recording Candylion I tried my hand at it on Spanish guitar. "

"Musically, it's so beautiful. It's one of those classical voices from that time. Ladies singing the blues: the title is very powerful. It's a woman singing her problems. The blues to me is when you cannot cry about your problems, you have to sing them. It's a kind of survival song. She's crying inside but she transforms her voice into a kind of hope."

"I was playing guitar when this came out and I tried to learn all the riffs. I loved that idea of transforming the blues into heavy rock – taking blues classics and giving them a twist. A lot of the music was traditional blues songs, but the Stones had done the same thing in taking them and twisting them. So many British bands took blues songs and made them famous –there are people who think ‘Roll Over Beethoven’ was written by the Beatles, and a lot of people didn’t know who BB King was until Zeppelin made him famous. When I was young my friend’s brother played guitar. He was really into blues, playing Chuck Berry, and he would play all these old recordings, so I knew all of them. All those licks I heard, I would then hear Clapton and all those guys play. I saw Zeppelin at Bath Festival [in 1970] from a long way off – the violin bow solo with the echo chamber went on for hours, but they were great. I’d never been to anything like a festival before, and that was the first real one, I was on awe."