A black New Jerseyan, singer-actor Robeson was a football all-American at Rutgers, and his version of Ol' Man River in the 1936 movie of Showboat is definitive. But stifled by discrimination, he tried Communism, became a hero in the USSR and died in 1976, almost forgotten. When this play was staged in New York in 1978, many blacks, including Robeson's son, Paul Jr., said it was a distortion. It's hard to see why. Robeson is again portrayed by James Earl Jones, whose presence is worthy of the larger-than-life subject, and the play is nothing if not a tribute.