Netflix has been on a book acquisition spree over the past year, developing screen adaptations of dozens of novels, series, short story collections, and graphic novels. About 50 of these literary properties are being turned into series projects, while the screening service has announced plans to adapt only a handful into features—a list that includes Button Man by John Wagner, I’m Thinking of Ending Things by Iain Reid, Pashmina by Nidhi Chanani, and The Willoughbys by Lois Lowry.

Netflix has 139 million subscribers, and these properties will provide the streaming giant with features, series, and animated shows for the coming years. “There’s just no other substitute for the amount of work and creativity that goes into a book,” said Matt Thunell, v-p of original series at Netflix.

Adaptation has long played a role in Netflix’s development efforts, with Piper Kerman’s Orange Is the New Black (2013), Jay Asher’s 13 Reasons Why (2017), and Lemony Snicket’s A Series of Unfortunate Events (2017) all turned into ongoing series. “We have development teams who are reading all night and every weekend,” said Kelly Luegenbiehl, v-p of creative for international originals at Netflix.

Many of Netflix’s deals begin with Maria Campbell Literary Associates. In 2017, Netflix exclusively retained that agency for its book-scouting efforts to find English- and foreign-language titles to adapt from around the world, including from the U.S. “I’m on the phone with them every week, talking about what’s going on in New York, what’s new, and about library properties as well,” Thunell said. In addition, Netflix executives now attend such international literary rights events as the London Book Fair and the Frankfurt Book Fair.

Campbell’s agency has also helped the company forge deeper relationships with publishers. For example, Netflix is adapting Frank Miller and Tom Wheeler’s illustrated novel Cursed as a series and coordinating release schedules with Simon & Schuster. “That is the kind of partnership that we’re really craving,” Thunell said. “To get in early with publishers and do something that is really mutually beneficial.”

Netflix is starting to explore new relationships with authors as well. Last summer, the company inked an exclusive multiyear deal with American thriller novelist Harlan Coben, developing 14 of his projects into series and features for Netflix’s global subscriber base. The streaming company is sharing Coben’s material with global producers to get new perspectives on his work, exploring adaptations that could be made around the world. If producers overseas end up adapting one of these works, Netflix will share that foreign-language version with all of its subscribers rather than making a separate adaptation for English-speaking markets. “It’s fun to see how local producers would take that source material and get inspired to adapt it for their local market,” Luegenbiehl said.

Luegenbiehl noted Netflix’s interest in acquiring other “libraries of content” from certain authors but wouldn’t go into specifics. In November, the company announced plans for a “slate of premium animated event series and specials” based on a long list of Roald Dahl books. That series of adaptations was the result of a joint agreement with the Roald Dahl Story Company.

One Netflix project spawned its own literary offering during development. Henry Selick, director of Coraline, inked a deal with the company for an original stop-motion animation feature titled Wendell and Wild. Writer-director Jordan Peele and author Clay McLeod Chapman are working with Selick on the script, but Selick and Chapman are also writing a book based on the story for S&S. The Gotham Group represents Selick and S&S, and Eddie Gamarra—cohead of Gotham Group’s book department and a literary manager—will executive produce the project. “We’re very deep in the Netflix space,” Gamarra said. “They’ve been a great home for our projects.”

When Netflix’s creative executives discussed adapting Polish novelist Andrzej Sapkowski’s Witcher series, Luegenbiehl’s team dissuaded the producers from making a standalone film. Luegenbiehl recalled asking them, “How can you take eight novels and just turn it into a film? There’s so much material here. There’s so much that you can do.” She added, “Through a number of conversations, the producers got really excited about the idea of using the source material for a longer-running series.”

“Netflix executives can discuss the books in-depth,” said New Leaf Literary founder Joanna Volpe. “That’s why we are seeing such great adaptations: because they are reading it and getting to the heart of the books.” Volpe represents author Leigh Bardugo, and Netflix recently acquired the rights to adapt all the books in her Shadow and Bone trilogy and Six of Crows duology into a single series.

New Leaf film and television head Pouya Shahbazian first introduced Thunell to the series in 2012. A few years into his tenure at Netflix, he turned to Netflix’s treasure trove of data to reconsider the project.

Netflix divides its global viewers into “taste clusters” or “taste communities.” A New York magazine article counted nearly 2,000 of these taste communities that compose the streaming service’s global audience. Netflix has kept its viewership statistics and taste community designations mostly secret but revealed a few select audience figures in a letter to investors in January. The company estimated its adaptation of Josh Malerman’s Bird Box novel was “enjoyed by over 80 million member households” during its first four weeks on the service.

“There is one taste community that I’ll loosely describe as the intersection of romance and the supernatural,” Thunell said, citing fans of Twilight and the Vampire Diaries as examples. “We didn’t have an original series that catered to this audience and this taste community. That frankly gave me the confidence, after years of waiting to get into the deal, to actually do it.”

In January, Netflix greenlit eight episodes of the Shadow and Bone series, bringing together the creatives behind two popular Netflix projects: Eric Heisserer, the Academy Award–nominated screenwriter who adapted Bird Box, and Shawn Levy, who executive produced Stranger Things. “At Netflix, our entire philosophy is we want to make everything that we buy,” Thunell said. “I’m buying Shadow and Bone because I intend to make it.”

Buzzy series such as Shadow and Bone are attractive, but Netflix is not just looking for bestsellers. “It is a factor if people love the story,” Luegenbiehl said. “That’s something that we want to know about, but it’s definitely not the single determining factor in why we would adapt something.” She cited the development of The Protector, a superhero fantasy series loosely based on a Turkish novel by N. Ipek Gökdel, as an example of a successful adaptation without a global fan base. “It wasn’t even translated into English, but our producers really saw something in the inspiration of a Turkish superhero.”

Netflix shared the show (its first Turkish original) with its global subscriber base and has since renewed the series for a second season. According to Netflix’s January letter to shareholders, the show was “enjoyed by over 10 million member households” during the first month of global release on the service.

Netflix recently secured adaptation rights to Gabriel García Márquez’s One Hundred Years of Solitude—a deal that included the company’s promise to shoot the series in Spanish and film in Márquez’s native Colombia. “In the past, the prevailing wisdom would have been to have everyone speak English in order to make it a more global show,” Luegenbiehl said. But the executive found through her time at Netflix that “authentic” foreign-language properties can resonate with “universal audiences”—a realization that inspired her development teams to seek literary talent in other languages and other cultures. “We’ll continue to look to books to find new voices, especially as we’re expanding into the African continent,” she added. “There’s a lot of great literature there. We’re really actively looking to tap into some stories there that perhaps didn’t have the right platform to be told on a global scale before.”

Both executives see literary material as an irreplaceable resource. “The reason I love books—especially a book-to-series translation—is that they often provide this incredible landscape, mythology, and opportunity for worldbuilding that’s really hard to come by in the everyday pitches I’m hearing,” Thunell said.