Damn! I kept thinking it was Styx, because that's the only prog band I know of that had "one" keyboardist who sang and wrote songs. (Kansas had technically two, as did Supertramp; and the English bands generally had a separate lead singer.) But guess what: I've only ever listened to the greatest hits albums, "Pieces of Eight" and "Cornerstone". I've never listened to the "Grand Illusion" album at all. I think "Cornerstone" was so disappointing I just never pursued the Styx route after that.