Coming off this summer’s deadly box office, with domestic ticket sales the lowest they’ve been in more than a decade, studios and beleaguered theater owners are looking to the highly anticipated horror film “It” to scare up some serious business as the fall moviegoing season gets under way.

The R-rated adaptation of Stephen King’s 1986 novel of the same name is projected to debut this weekend to at least $60 million, and potentially go on to amass tens, if not hundreds, of millions more during its run in theaters, on home entertainment platforms and in other ancillary markets. A follow-up film is already expected to begin production in the first quarter of next year.

Stocks of the country’s major theater circuits — AMC, Regal Entertainment, Cinemark and Imax — have been getting pummeled by the downturn. Summer box office, which ended on Labor Day, was down more than 20% from 2016, and year-to-date revenue is off 6%.

King, who was not involved with the making of the movie, says he’s excited about the film, which he describes as “fabulous.” The author even recorded a short video that introduced an extended theatrical trailer of the film in August. He says he has only one issue with the upcoming adaptation of his book. “Geez, I don’t even think they sent me any swag,” he jokes in a recent phone interview with Variety. “But maybe that’s a good thing.” (Producer Barbara Muschietti assures us that King has since been sent “a truckload” of swag.)

Zach Meyer for Variety

Film adaptations of King stories have run the gamut from Oscar-worthy — see “The Shawshank Redemption” and “Misery” — to disastrous, such as the recent attempt to launch “The Dark Tower” as a movie franchise and TV show. The first film, released in late July, was ignored by audiences and panned by the critics. This weekend, “It” is expected to break the record for biggest opening weekend of a non-sequel, R-rated horror film, currently held by “The Conjuring,” which debuted to $41 million in 2013.

Not bad for what producer Seth Grahame-Smith calls “an R-rated movie starring 13-year-old kids.” It was also a film that underwent many changes, was stalled, and switched directors since it was first announced by Warner Bros. in early 2009. The result, says Grahame-Smith, is “a culmination of more than six years of trying to get the book made — and made the right way.”

The film is the first in a planned duology. The novel itself centers on seven kids coming of age in 1950s small-town Derry, Maine, who dub themselves “the Losers Club.” They battle an evil entity known as “It,” which can take the form of whatever you fear, though it’s most commonly portrayed as a grinning clown known as Pennywise. And 27 years later, when they’re adults, “It” returns to their hometown. ABC aired a miniseries adaptation in 1990, starring Tim Curry as Pennywise, and cut between the two timelines. But the new film focuses only on the early years of the story.

When Warners announced the movie eight years ago, it marked a reunion for producers Dan Lin and Roy Lee and writer David Kajganich, all of whom had worked together on 2007’s “The Invasion” for the studio. Shortly thereafter, Grahame-Smith and his producing partner David Katzenberg came on board. In 2012, director Cary Fuku­naga signed on to direct after he proved he could handle an adaptation of a beloved novel with 2011’s acclaimed “Jane Eyre,” and went to work on the screenplay with Chase Palmer, whittling down King’s 1,100-plus-page opus.

In 2014, as the project took on more steam thanks to the success of the first season of Fukunaga’s HBO series “True Detective,” Warner Bros. moved “It” over to its New Line division. New Line has a strong horror history thanks to its highly successful “The Nightmare on Elm Street” franchise — earning the film company the nickname “The House That Freddy Built.”

In May 2015, Fukunaga announced the casting of Will Poulter (“The Revenant”) as Pennywise. But before the month was over, Fukunaga had dropped out (Poulter eventually followed). Rumors circulated he was unhappy with New Line’s proposed budget of $32 million, but in a September 2015 interview with Variety, Fukunaga dismissed that notion. “It was the creative that we were really battling,” he said. “They wanted me to make a much more inoffensive, conventional script. But I don’t think you can do proper Stephen King and make it inoffensive.” Upon the announcement, King tweeted: “The remake of IT may be dead — or undead — but we’ll always have Tim Curry. He’s still floating down in the sewers of Derry.”

But, not unlike a character in a King novel, “It” rose again. Like so many in Hollywood, Argentine filmmaker Andy Muschietti and his sister-producer, Barbara Muschietti, had been tracking the project.

Their 2013 film “Mama” proved a good mesh of horror and character and grossed more than $146 million worldwide. “We had a good relationship with New Line and set a meeting,” notes Barbara Muschietti, the downside being that they had only four days to prep, during which time her brother reread the entire book.

“It” director Andy Muschietti lines up a shot. “It’s a horror movie,” he says, “but also a character-driven drama with comedy and emotion.”

Of their initial meeting, Andy Muschietti acknowledges, “I started on the wrong foot. I opened my notebook, and it was full of all these napkins with my writing and drawings. There was a 20-second silence where they all fell to the ground and I was picking up what was essentially my pitch.”

But Grahame-Smith and Katzenberg weren’t worried. “Andy stood out immediately because he came in talking about the book,” Grahame-Smith says. “People would come in and talk about set pieces and jumps and clowns. Andy came in talking about the kids and the Losers Club and his experience being a teenager in Argentina reading this book. We knew it was in his heart, and he was going to care for it the way we wanted to care for it.” Katzenberg adds that the napkins were actually impressive. “He’s a fantastic artist; some of those doodles really got me excited.”

Andy Muschietti signed on to direct in July 2015 with an eye toward a summer 2016 shoot. “We wanted to do it before our cast went off to school,” Katzenberg says. Gary Dauberman, who penned “Annabelle” and its hit sequel for New Line, was brought on board to rework the script, though Fukunaga and Palmer retain writing credits.

“I looked at it as picking up the ball and running with it,” Dauberman says. “There were some smart decisions made early on that we kept — one of them being that the focus would be on the kids for this movie.” At one time, Warner Bros. had hoped to make one film of the entire story. But Katzenberg says that idea was quickly scrapped, noting, “It would have been a five-hour movie.” Even with just telling the first part of the story, Dauberman says it was tough to eliminate parts of the book. “Your choice is between great … and great,” he says.

The biggest challenge was incorporating all the different tones King covers in his stories. “It’s a horror movie, but [also] a character-driven drama with comedy and emotion,” says Andy Muschietti. Barbara concurs, “I would say his best adaptations don’t try to settle on one tone. His books are a roller coaster, and his movies should reflect that.”

What does King think makes a good adaptation of his work?

“I think it’s good when they stick as close to the story as they can because that’s what they bought,” he says. “You don’t want to think they just bought the launching pad, but they bought the rocket too.”

The author also appreciates effort: “I’m a workhorse myself, and I like people who work hard. I like people who are creative, who are visual, who come to it with a professional attitude and have an artistic flair.”

A significant change to the story was in updating the start of the events 30 years. “When King wrote the book in the ’80s, that nostalgia was about the ’50s,” Grahame-Smith explains. “Now it’s about the ’80s.”

The period resonates more than they could have imagined: “It” was in production in Canada in July 2016 when an unknown series set in the ’80s called “Stranger Things” premiered on Netflix. Comparisons were inevitable, and the projects even share an actor; Finn Wolfhard, who was chosen out of hundreds to play Richie Tozier in the film, stars as Mike in the hit series. “I think we knew he had done something called ‘Stranger Things,’ but we didn’t really know what it was,” Barbara Muschietti admits. She adds that when production started, Wolfhard had 400 followers, and by the time it ended, he had 1 million.

As for the correlations, Katzenberg says, “It’s kind of a bummer some people think ‘Stranger Things’ came before ‘It’ did.” But he adds, “If that brings more people to see our movie, great.”

King also thinks nostalgia for the 1990 miniseries plays a big role in the current buzz. He points to the first teaser for “It,” which broke the record for most-viewed trailer online in a single day with 197 million views. “When that hit and everyone went bonkers, I think a lot of that excitement came from people who were 14 when the miniseries came on and it scared the shit out of them,” King says.

But the filmmakers took pains to differentiate the movie from the miniseries. “The last thing anybody wants to do is riff on what Tim Curry did,” Grahame-Smith says. “You had to create something new and iconic.” Andy Muschietti notes a lot of that fell to Bill Skarsgård, who was cast as Pennywise. “Bill built the character to have a more intellectual dimension or hint at where he comes from. There’s a lot of thinking about the character that’s not necessarily reflected in the movie. I won’t rule out more developing will happen in the second half.”

While the second film technically hasn’t been greenlit, it seems inevitable as “It” races toward a record-breaking opening.

The producers are coy about even discussing a part two, while Andy Muschietti says, “I don’t think it’s a sequel; it’s a second half to the story.”

So he’d be up for returning? The director doesn’t blink. “One hundred percent,” he says.