Curtis Mayfield: The Speakeasy, London

THE ALL-too-brief, spur-of-the-moment appearance of Curtis Mayfield at London's Speakeasy club must surely rank as a historic event in the history of soul music in this country. Historic because it was the first time Mr. Mayfield had played in front of a British audience (albeit a totally unrepresentative one) and historic because it proved that if the term "superstar" still has any meaning (the word has been misused so much that the true number of "superstars" is infinitesimal), Curtis Mayfield is already there.