The culmination of the Golden Age of the American musical

In the 1920s and 1930s, musical theatre songs were written with the intent that they could change placement in a show, or be removed from a show completely and stand on their own. Whether written as popular songs, or for revues or book musicals, the popular songs far outlasted the shows in which they first appeared. With the advent of the integrated musicals of Rodgers and Hammerstein in 1943, songs were used to advance either character or plot. But the music of the musical theatre still crossed over to be recorded by popular singers like Eddie Fisher, Doris Day, Rosemary Clooney and Louis Armstrong. Financial rewards were high for Broadway composers and lyricists who wrote songs for their shows that became hits. For a song to cross over in this way, it needed to be less specific to the character and situation, and roughly two and a half to three minutes long. Song structure was frequently A-A-B-A, sometimes with a repeat of the B section as an instrumental and a final sung A section with a coda. Of course other structures existed, but composers had to keep in mind that the song had to adapt to this kind of structure for the popular recordings that could bring in so much money.