In honor of the 75th anniversary of Oklahoma!, the New York Public Library for the Performing Arts at Lincoln Center has mounted a special exhibit, Celebrating 75 Years of The Rodgers & Hammerstein Musical, currently open free to the public through September 23.

A landmark of the musical theatre canon, Richard Rodgers and Oscar Hammerstein’s Oklahoma! is often credited by early theatre historians for being the first American book musical—though today we recognize shows like The Black Crook, Show Boat, Pal Joey among the first. While it may not be the first book musical, Oklahoma! did set landmark firsts, particularly in choreography. As the exhibit showcases, choreographer Agnes de Mille was the first to weave storytelling and dance (rather than use dance as a breakaway or rest from the plot).

The first installation in the exhibit is a video wall that showcases archival footage from the films of Oklahoma! and Carousel as well as rehearsals for stage productions paired with glimpses of de Mille’s original choreographic notes.

Oklahoma! also marked innovation in producing, as Rodgers and Hammerstein worked with the Theatre Guild’s Theresa Helburn to adapt Green Grow the Lilacs into the musical. She also brought Liliom over, which the duo adapted for Carousel. The Theatre Guild photo wall features pictures of Helburn and her productions, including both of the Rodgers and Hammerstein musicals, and original artwork used to promote her many shows.

The adaptation of Green Grow the Lilacs into Oklahoma! takes center stage with the interactive display of the earliest scripts of both iterations annotated by Rodgers and Hammerstein.

The wall also chronicles the historical backdrop of Rodgers and Hammerstein’s works. “[Oklahoma and Carousel] were the first two musicals that Oscar Hammerstein and Richard Rodgers wrote together, and they both came out during World War II,” explains exhibit curator Doug Reside. “Theresa Helburn was trying to raise money [for theatre] right at the time people were trying to raise money for the war … but both musicals were enormously successful. I theorize that one of the reasons both were so successful is that they spoke to the anxieties people had on the homefront during WWII.

“I also look at Billy Bigelow as perhaps a representation of PTSD,” he continues. “Men are coming back from the war by 1945, and Billy Bigelow is very similar to documentaries and news footage and PSAs and veterans coming back form the war and dealing with what they called shell shock of that time.”

Thanks to the NYPL archives, viewers can also examine artwork produced in association with these two famed musicals, including original Hirschfeld caricatures and posters for productions over the past 75 years.

Then, there are the faux department store windows, emulating what stores would have looked like back in 1944. “Oklahoma! was the first cast recording to have the original cast and the original orchestra doing most of the songs from the original production,” says Reside. “The album was a many-disc album sold in stores as a souvenir item, but also used to promote the show around the country.”

Carousel earns the spotlight on the second floor of the exhibit, which highlights designs by Jo Mielziner, whose archive lives at the NYPL. “We have one major design for every scene in Carousel as well as a photograph from the show,” Reside says. “You can see the work of one designer through many stages of the process.”

Don’t miss the full exhibit up close at the New York Library for the Performing Arts in Manhattan, open through September 23.