Guests Keith Emerson, Greg Lake and Carl Palmer each had a hand in actually defining the Prog Rock sound, albeit individually in separate bands, Emerson as a keyboard innovator with The Nice; Greg Lake writing and singing on the 1969 King Crimson groundbreaker In the Court of the Crimson King; and Carl Palmer exhibiting power and space-filling percussion in the trio Atomic Rooster.

ELP's fourth studio album and biggest seller Brain Salad Surgery is an eclectic adventurous collection, starting with the album opener "Jerusalem" featuring lyrics by English poet William Blake; the over-the-top synthesizer and electronic percussion in "Toccata" occurs while re-interpreting Argentinian composer Albert Ginestera's "First Piano Concerto, 4th Movement"; "Still You Turn Me On" continues the gorgeous Greg Lake ballads; and the album centerpiece "Karn Evil 9″ was uncannily prescient by predicting the Computer Age a full four decades ago according to Greg Lake talking to InTheStudio host Redbeard.