No relation to this, of course, John Mayall's Bluesbreakers playing On Top Of The World.
The couple of little guitar breaks are Eric Clapton inventing modern electric guitar. It was produced by Jimmy Page. There's a bit of difference between 1935 Mississippi Delta and 1965 London (to say the least) but given my own situation, I heard the Bluesbreakers first. This track, and the others at the same time - I'm Your Witchdoctor, Telephone Blues - will always be my touchstone tracks.