Keith Emerson's brash and playful arrangement of the 4th Movement of Alberto Ginastera's Concerto for Piano No. 1 combined ELP's passion for classical music with their fascination with state-of-the-art musical technology — the track may have been the first commercial recording to feature pre-programmed electronic percussion. The band initially met with resistance from Ginastera's publishers when they asked for permission to include "Toccata" on 1973's Brain Salad Surgery, so Emerson flew to the composer's home in Switzerland to plead his case in person. "I had a nice lunch with Alberto and his wife and then I played the tape for him," Emerson recalled in 2014. "When it was over he had this strange look on his face. He looked like he was in pain! And he said something like, I can't remember the exact words but something like, 'That is horrible!' I thought, Oh God, he hates it! And I was ready to go home. But his wife said to us: 'No, no, no, he says 'diabolical' in a good way, like 'unbelievable!'" Ginastera's personal endorsement of the track — "Keith Emerson has beautifully caught the mood of my piece" — would be included in Brain Salad Surgery's liner notes. D.E.