“Seen from the point of view of the composer, the most nonsensical practice is that of casting people in musicals who are unable to sing. No one would cast a dancing part with someone who cannot dance sufficiently to come up to professional standards. The same is true of acting. But when it comes to singing, more often than not it is amateur night. . . . Either musicals should be written for specified performers in the first place, or they should be cast with people who are adequate to its dancing, acting and singing demands.”