Show Boat and Of Thee I Sing both look forward to a new sophistication of the musical that came about in the 1940s. Now the plots of musicals were worked out with more care. Instead of being a mere pretext for songs and dances in the manner of a revue, the plot had interest in its own right, and musical numbers grew logically out of it.

Richard Rodgers (1902–1979) and his lyricist Oscar Hammerstein (1895–1960) dominated this period. Their works, such as Oklahoma! (1943) and The King and I (1951), ran for thousands of performances on Broadway. To this day they define the golden age of the musical — perhaps especially because they offered a sentimental and innocent vision of the world as America in the postwar era wished to see it. It is a vision similar to Aaron Copland’s in Appalachian Spring (see page 349).

Other musicals tackled more challenging subjects — racism, trade unionism, gangs — but these rarely rivaled the megahits of Rodgers and Hammerstein. One exception to this rule is West Side Story, with music by the classical composer and symphony conductor Leonard Bernstein. Here we see the cultivated tradition reaching out to the vernacular — but in a genre defined by the vernacular.