(Charles Kruger) (Rating: *****) (“Showboat” plays at the War Memorial Opera House from June 1st through July 2, 2014.) “Showboat”, an uneqivocal masterpiece, is the first great American musical play. Drawing on the tradition of European operetta, the Mississippi river showboats from which it gets its title, the minstrel show tradition and the Broadway stage, it lays […]