One of my first outings while recovering from a little stroke has been to the New London Theatre in Drury Lane to see the splendid revival of Show Boat, the 1927 musical of Jerome Kern and Oscar Hammerstein II. Show Boat not only contains some of Kern’s finest songs (‘Ol’ Man River’ and ‘Can’t Help Lovin’ Dat Man’, for example), but is remarkable as the first American musical to combine light entertainment with a dramatic story and to deal with serious themes — gambling, alcoholism and racism.