ELP songs started with the music and had to stand on their own before they would consider vocals. In our interview with drummer Carl Palmer
, he said: "'Knife Edge,' which was the only rock track on the very first album, was something which came together very, very quickly in the studio and really worked - it was fantastic. We thought it was an instrumental, and Greg said, 'No, hang on.' He said, 'I could put a topline on this, we could have something.'"