When Richard Rodgers and Oscar Hammerstein II were approached about turning Broadway’s Oklahoma! into a movie, they were reticent. After all, the stage show had been a revolutionary success, and this was at a time—1955—when musicals were often butchered on their way to the screen. That the end product stayed faithful to their vision was due in part to the control Rodgers & Hammerstein were able to leverage over production. But the Oklahoma! soundtrack also reinforced what had made the show so great in the first place: While musicals until that point were more or less plays interrupted by the occasional song, Oklahoma! envisioned musicals in which the songs themselves were instruments of plot and character development—a shift that brought the form closer to something like American opera than light entertainment. So when Gordon MacRae’s Curly McLain sings “Oh What a Beautiful Mornin’” and “The Surrey With the Fringe On Top,” they aren’t just good melodies—they’re expressions of his cowboy charm and his budding crush on Laurey (Shirley Jones). And when the cast joins Curly for the title song near the end, it’s after a couple of hours of us getting to know the sweet-wheat-smelling, plains-wind-swept frontier where the story took place. The soundtrack held the top spot on the UK Albums Chart for a stretch in 1956, eventually becoming the first album certified gold by the Recording Industry Association of America. That spring, Elvis came along, ushering in a demand for all things rock ’n’ roll. But the Oklahoma! soundtrack would retain its power, and appeal, for generations.