When Rodgers and Hammerstein’s “Oklahoma!” debuted on Broadway in April 1943, everything was going its way — except that it opened smack-dab in the middle of a calamitous recording strike. Eight months earlier, the American Federation of Musicians had enjoined its members from entering any recording studio, and the music industry was scrambling with halfhearted solutions: back catalog releases, previously shelved recordings, a cappella renditions — dreadful stuff.

To capture the “Oklahoma!” fever, both Bing Crosby and Frank Sinatra cut 78 r.p.m. recordings of “People Will Say We’re in Love” on the A-side and “Oh, What a Beautiful Mornin’!” on the B-side. Each recording was a hit on the charts, but the renditions were lugubriously weighed down by a cappella backup; they sounded nothing like the highly-praised music that lucky theatergoers were enjoying eight times a week on Broadway. From a record producer’s perspective, a potential gold mine was withering away down at the St. James Theater.

That’s when Jack Kapp, the farsighted president of Decca Records, threw in the towel and settled with the musicians’ union. In doing so, he helped create a product that revolutionized the recording industry : the original cast album, which from the 1943 Broadway version up through the current revival’s brand-new recording, has been one of the most durable categories in American music .