Prelude: After the Gold Rush

Prelude were a folk group, formed in Gateshead in 1970 and active until recently.

This 1974 a capella version of a Neil Young song was their finest hour. It charted around the world, reaching number 21 in the US and number 22 in the UK.

What is it about? Wikipedia offers a choice of answers:

Dolly Parton (who was in the process of recording a cover of the song along with Emmylou Harris and Linda Ronstadt) has said, "When we were doing the Trio album, I asked Linda and Emmy what (the song) meant, and they didn't know. 

So we called Neil Young, and he didn't know. We asked him, flat out, what it meant, and he said, 'Hell, I don't know. I just wrote it. It just depends on what I was taking at the time. I guess every verse has something different I'd taken.'"

However, in his 2012 biography Young reportedly gave a different explanation of the song's origin and meaning, describing the inspiration provided by a screenplay of the same name (never produced), which apocalyptically described the last days of California in a catastrophic flood. The screenplay and song's title referred to what happened in California, a place that took shape due to the Gold Rush. 

Young eventually concluded that “After The Gold Rush is an environmental song... I recognize in it now this thread that goes through a lotta my songs that’s this time-travel thing... When I look out the window, the first thing that comes to my mind is the way this place looked a hundred years ago.”