"Music and girls are the soul of musical comedy," one critic wrote, early in the 1940s. But this was the age that wanted more than melody and kickline form its musical shows. The form had been running on empty for too long, as a formula for the assembly of spare parts--star comics, generic love songs, rumba dancers, Ethel Merman. If Rodgers and Hammerstein hadn't existed, Broadway would have had to invent them; and Oklahoma and Carousel came along...