A musical depends on a mix of elements—singing and dancing, music and movement. But what makes a musical more than a collection of songs is an often unassuming component known as the book. More than just the spoken dialogue in a musical, the book is what grounds a work in a narrative world.

But the book is often the least overt, and least appreciated, element of a great musical. Can’t recall the dialogue from West Side Story? Arthur Laurents’s words can’t help but sit in the shadow of Leonard Bernstein’s score and Jerome Robbins’s choreography. By contrast, when a book doesn’t work—when it feels sloppy or heavy—it’s far more noticeable.

“People might not walk away from a musical thinking, ‘God, that text was fantastic,’” says Greg Pierce, whose first musical, The Landing, premieres this month at the Vineyard Theatre in New York. When Pierce, who wrote The Landing’s book and lyrics, recalls his favorite books of musicals, he lists Cabaret, Assassins and West Side Story, but then admits, “If I haven’t seen them in a while, I can’t actually remember if I loved the book itself. I just love the show, the totality.”

And that’s often the point. It’s why books are—in more ways than one—the unsung heroes of musicals.

Itamar Moses spent a decade writing plays before exploring the terrain of musicals. Feeling limited by the “inherent formal constraints” of sticking to one genre of theatre, he felt compelled to test other forms, acknowledging that by creating a musical he would have to give up the solitary autonomy that playwrights enjoy. A book writer “has to be ego-less in a way that I think playwrights aren’t used to, but which I think is healthy,” Moses remarks, explaining, “If I do my job perfectly, someone else is going to get an enormous amount of credit.”

Moses’s entry into musicals began with Nobody Loves You, an original work that sets an unconventional romance within the fictional reality dating show of the title. Moses wrote the book and lyrics alongside composer and childhood friend Gaby Alter, crafting the story together over six years. In that time, Moses began to see book writing as “a supporting role in a very literal sense—you’re building the foundation and scaffolding for the building. And by the time the building is done, the foundations should be invisible and the scaffolding gone—because you did it right, the building looks great.”

Nobody Loves You premiered at San Diego’s Old Globe in the spring of 2012, then bowed at New York’s Second Stage Theatre this past summer. Moses says he and Alter had an “aggressive and unsentimental” approach to developing their show, which involved countless script changes and a dozen rewritten songs. The process has been, Moses admits, one of the hardest of his career, in no small part because of the team’s decision to develop the show their own way.

“We wrote an original musical that wasn’t based on a famous book or a movie. We didn’t put a star in it. We hired the director we’d been working with [Michelle Tattenbaum], as opposed to someone with 10 Tony Awards. We went to San Diego without any commercial producers attached to it. We did everything you’re not supposed to do,” he reflects. “And maybe there’s a lesson, it’s going well so far.”

Moses’s next project will be an adaptation of Jonathan Lethem’s novel The Fortress of Solitude, slated for its premiere at Dallas Theater Center in March 2014. The new musical, which features songs by Michael Friedman (Bloody Bloody Andrew Jackson), emerged after director Daniel Aukin secured the rights to the novel and sought out Friedman and Moses to adapt it.

Converting a “tapestry-like” novel to the stage has its own challenges. In writing the book for Fortress, which portrays boyhood friends in pre-gentrified Brooklyn, Moses realized that it would be impossible to simply transfer the story’s narrative to staged scenes. “We had to figure out how to translate Lethem’s literary metaphors into dramatic metaphors. My job is to identify when he’s done that and foreground those things.”

By the same token, adapting a literary work offers specific source material, which lends a more direct access point for book writing. “I didn’t consciously think, ‘All right, so how did people talk in the ’70s in Brooklyn?’ I had the novel, and I had Lethem’s dialogue.”

Pierce also had prose fiction on his mind when writing The Landing—specifically, the literary concepts of first- and third-person narrators. A short story writer himself who had only recently ventured into playwriting, Pierce was not actively looking to pursue musicals until a venerable composer made an enticing offer. John Kander, the co-creator of Cabaret, Chicago and The Scottsboro Boys, found that he was still inspired to write music after the passing of his longtime lyricist partner Fred Ebb in 2004.

Pierce and Kander first met at an alumni event at Oberlin College. Kander was known for lending support and feedback to Oberlin graduates pursuing writing and musical theatre, and Pierce began sending Kander his short stories to read. After several years, Kander confessed that Pierce had become one of his favorite short-story writers and asked the younger man if he’d like to collaborate on a musical. Their combined enthusiasm for the project eased Pierce’s acclimation to the new partnership. It helped that there was no imperative to replicate the Kander-Ebb model.

“How John and I work together is very different from how he worked with Fred,” Pierce says. “He and Fred were always in the same room. John and I don’t write like that. Whoever has the first impulse will commit it to paper, and we’ll bring it in and play around with it. Also we both have iPhones now, which is so amazing—John lives upstate, so he’ll write a snippet and put it on his voice memo and text it to me, and then I can play it over and over and keep experimenting with it.”

Their first creative impulse was “the idea of a narrator, the idea of a short story onstage,” Pierce recalls. The Landing has evolved into a triptych of one-act musicals, linked by the presence of an observational speaker, who differs from act to act. “In theatre, all you have is what is spoken,” Pierce says. “You never have the interior voice. That’s totally fascinating to me, to have a narrator who can comment on the action in a literary, novelistic kind of way.”

The Landing will feature actor David Hyde Pierce, who starred in Kander and Ebb’s 2007 Broadway production of Curtains and also happens to be Pierce’s uncle. Regardless of how The Landing is received by audiences, the Kander-Pierce duo will not be a single-occasion partnership: They are already at work on another musical.

One clear draw for playwrights interested in musicals is the opportunity
to create theatre with a new group of artists. Longtime writer and performer Lisa Kron discovered a new fascination with composers while working on her first musical as book writer and lyricist.

“There’s that game where people say, ‘If you could choose a superpower, what would it be?’ I think now I would say music: to be able to sit at the piano and do what Jeanine can do.” She means composer Jeanine Tesori, with whom she has teamed up on a musical adaptation of the graphic novel Fun Home by Alison Bechdel, starting performances at New York’s Public Theater this month.

Though Kron was enamored of the original work, which portrays Bechdel’s fractured relationship with her father, she found the narrative and characters unusually hard for a musical adaptation—her first such effort.

“There are two major things that happen in the story, but apart from that, the characters are leading daily lives,” Kron says. “They’re also emotionally repressed people, so we’re writing songs for people who don’t know what their emotions are, and a book in which there are virtually no events.”

To make those subtleties work for a musical, Kron took a word of advice from director George C. Wolfe, whom she quotes as saying, “[In a musical] the person has to want one thing, and it has to be a life-and-death thing, and you have to say it really clearly, and then you can be as complicated as you want.”

Nearly all musicals go through a substantial development process, typically far longer than for plays. To spend multiple years on a project, engage producers and ultimately sell tickets is a risky endeavor, which is in part why artists who create musicals, newcomers and veterans alike, tend to pursue adaptations of pre-existing material.

Some see the reliance on adaptation as a creative constraint, but not Marsha Norman. The Pulitzer-winning playwright (who has become an award-winning book writer) is an ardent advocate of adaptations. This past summer at Massachusetts’s Williamstown Theatre Festival, she presented The Bridges of Madison County, which transfers to Broadway this season. Counting Madison County, directed by Bartlett Sher and featuring songs by Jason Robert Brown, Norman has done four musical adaptations with cinematic as well as literary pedigrees; the others are The Secret Garden, The Color Purple and The Red Shoes.

“I encourage people not to do original musicals,” says Norman, who teaches playwriting at Juilliard, “because part of what’s fun about a musical is giving people another experience with something they already love.” She adds, “The audience is going to drift toward the shows that they already know, because that’s what audiences do.”

Many would take issue with that approach, and theatre critics regularly bemoan the Hollywood takeover of musicals, recently exemplified by the announcement that 20th Century Fox, the film studio, has created a theatrical division to develop its films into musicals. But from Norman’s perspective, the trend deserves more celebration than scorn. She is confident in focusing her talents entirely on musical adaptations.

“Now that I’ve done four,” she says, “people are starting to say, ‘Oh, she’s really serious. She’s not doing plays anymore. She’s really changed gears.’ And it’s true, I have.”

That’s not to say these have been impersonal writing-for-hire gigs for Norman. She believes that, with any show, a writer should pull from his or her “stuff,” a term she uses to describe the central themes or ideas with which a writer grapples. “You don’t take the job unless it’s got your ‘stuff’ in it,” she reasons. “I mean, I look at The Color Purple, The Secret Garden, The Bridges of Madison County, they all have my stuff in them, which is the trapped girl. That’s what I write about.”

Moses found his “stuff” in Nobody Loves You in the form of the show’s main character, Jeff, whose relationships are inhibited at first by an intellectual remove. “For my first musical, I had to write a story about someone who couldn’t open up easily to the kind of sentiment you want in a musical,” Moses says. “And to tell the story of him getting to that place.”

 Lonnie Firestone writes frequently for this magazine.