The clearest candidate for America’s favorite fairy tale might be The Wonderful Wizard of Oz. The author L. Frank Baum set the novel, published in 1900, in a fantasy land that shares core American values: self-sufficiency, personal reinvention, the exploration of wider frontiers. The book’s young heroine, Dorothy, is whisked away to Oz, where she befriends magical creatures, thwarts a witch, and leans on her newfound strength and friends in order to return home. For Dorothy, it is a land of empowerment and possibility; for Baum—who perpetuated manifest destiny’s warped ideals in his other writings—and his many readers, it was an otherworldly representation of the American expanse, a place they perhaps wanted to see for themselves.

Baum’s novel and its sequels were major literary phenomena in their day. But Oz persists primarily through the books’ many adaptations, which established the series’ enduring iconography. Baum’s world is best remembered as it has appeared on-screen, especially in the 1939 musical film starring Judy Garland as Dorothy: a place bursting with songs such as “Over the Rainbow” and visuals such as the yellow brick road, which have become the franchise’s most memorable features. And with The Wonderful Wizard of Oz’s 1956 entry into the public domain, allowing for new, noncanonical works, subsequent generations have iterated on these hallmarks to tell Oz stories of their own.

No transformation has been more vital to Oz’s longevity than Wicked, the revisionist origin story of the Wicked Witch of the West, one of Baum’s most recognizable villains. Based on the author Gregory Maguire’s 1995 novel of the same name, Wicked’s prominence is up there with that of its source text, and yesterday’s release of the first part of the musical’s highly anticipated film adaptation will undoubtedly broaden its reach. Key to Wicked’s success—and its ability to bridge Oz’s past and future—is its canny understanding of what, exactly, makes that world work so well.

Artists across genres and mediums have, for decades, found great storytelling potential in Baum’s characters and mythology. But the mode that Oz has continued to lend itself to best is musical theater, a genre predicated on suspension of disbelief and thus well suited to conveying Oz’s odd earnestness. The Wizard of Oz’s 1903 Broadway musical debut was a hit, firing up demands for more stories, which prompted Baum to write a total of 13 sequels to his book.

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The Garland film, inspired in part by the success of the musical, cemented Oz’s connection to music, but it was The Wiz that brought it back to the theater, in 1974. The latter was the franchise’s first majorly reenvisioned entry, a celebration of Black culture that took Dorothy’s story to the 1970s. During its four-year run on Broadway, The Wiz earned several Tony wins; the (less well-received) film adaptation notably starred the then-superstars Diana Ross and Michael Jackson as Dorothy and the Scarecrow, respectively. The Wiz showed that Baum’s novel could be successfully reinterpreted within a contemporary frame, and its story and characters updated accordingly. This transposition didn’t sacrifice the core imagery and themes—Dorothy still fights off flying monkeys and dons magic slippers to make it back home—but instead retained and even grew their cultural power.

Oz hasn’t translated as well into dramatic, adult-oriented settings, despite numerous writers’ and filmmakers’ efforts. The 1985 Disney film Return to Oz reintroduced the world by utilizing lesser-known characters from Baum’s later books; although it exhibited Oz’s compelling peculiarities, such as sentient furniture and disembodied human heads, it was a critical and box-office failure, deemed too dark for young viewers. Science-fiction authors including Robert Heinlein, Philip José Farmer, and even Stephen King wrote stories incorporating Oz that received mixed reviews. The Syfy miniseries Tin Man and NBC’s one-season flop Emerald City also mostly failed to resonate. Only Maguire’s Wicked: The Life and Times of the Wicked Witch of the West—a tale laden with adultery, murder, and slavery—has taken hold of the popular imagination. Wicked has become the contemporary Oz text, perhaps even superseding Baum’s work: It carries forward the original novels’ mix of campy magic and violent spectacle while bringing in modern literary themes. Maguire’s biggest change was recasting Baum’s antagonist as the antihero, reframing a straightforward villain as a woman misunderstood by her peers—an experience likely more relevant to today’s readers than Dorothy’s simpler tale of good versus evil.

Wicked used Oz’s whimsy and weirdness to deepen Baum’s seemingly unambiguous world, one strictly divided between right and wrong. The basic premise was a powerful one: What if the Wicked Witch of the West wasn’t so bad after all, and what if the Wizard—and the seemingly perfect society he oversaw—was the real threat? In his retelling, Maguire, an Oz fan since childhood, named Baum’s one-dimensional and green-skinned villain Elphaba Thropp; he also gave her a complicated parentage, a soapy romantic arc, and a dorm room. She attended Shiz University alongside a diverse spread of colorful, slang-talking Ozians. And, developing a darker side to Baum’s fanciful creation, Maguire also gave Elphaba a political motivation for wreaking havoc on her homeland: the oppression of its talking animals. But Maguire’s most important addition was the college friendship between Elphaba and Glinda the Good Witch (one of the Wicked Witch’s sworn enemies in Baum’s novel); the musical turns that bond into its emotional core.

[Read: Hollywood’s new crown prince of musicals]

The 2003 Broadway adaptation lent some of the Garland-led film’s sparkle to Maguire’s story and made it appropriate for an all-ages audience. By foregrounding Elphaba and Glinda’s relationship, the musical emphasized Baum’s thematic interest in friendship and self-discovery. Theatergoers could relate to Glinda’s perkiness and craving for popularity and Elphaba’s fish-out-of-water awkwardness the same way they could, in watching The Wizard of Oz or reading Baum’s novel, imagine themselves in Dorothy’s shoes, searching for home. By simplifying Maguire’s plot, the musical better captured the fairy-tale feeling of Baum’s novel. Since its opening, its appeal has proved universal—Wicked has become the second-highest-grossing Broadway musical of all time.

Its success has also translated offstage in a particularly generative fashion. Wicked is now the jumping-off point for numerous fanworks—a meta development, because the show itself is a fanwork of a fanwork. Fan fiction based on the musical has become a genre unto itself; many works imagine a queer relationship between Elphaba and Glinda. Showstoppers such as Glinda’s bubbly “Popular” and Elphaba’s anthemic “Defying Gravity” are well-orchestrated articulations of the show’s ethos, inspiring amateur and professional renditions alike. Enamored artists and theatergoers often reimagine and revisit Wicked, as do budding Broadway lovers who haven’t attended an in-person production: An abundance of bootleg recordings has made Wicked one of musical theater’s most accessible entry points. It’s also a gateway into the broader world of Oz. Wicked and its own iterations—including its long-awaited film adaptation, which has already become a cultural event—work for the same reasons Baum’s original story did: They conjure a world that is buoyant, relatable, and unforgettable.

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