IT (2017/2019): Movie vs. Book, What Changed

2026-07-19

Spoilers for both the novel and both films follow.

Andy Muschietti's two-part adaptation — It (2017) and It: Chapter Two (2019) — is the most commercially successful Stephen King film ever made, but it takes real liberties with the source novel to get there. Some changes are just practical (a 1,100-page book with a dual timeline doesn't fit two films without cuts); others meaningfully change what the story is about. Here's what's different.

The timeline shift

The biggest structural change: King's novel alternates between 1958, when the Losers' Club are children, and 1985, when they return as adults. Muschietti's films split those into two entirely separate movies and shift both timelines forward 27 years — the kids' story now happens in 1989, and the adult reunion happens in 2016. It's a cosmetic change (it lets the first film use late-'80s nostalgia the way Stranger Things had recently made popular) that doesn't affect the plot, but it's the first thing longtime readers notice.

Losing the interwoven structure

The bigger consequence of splitting the story into two films is losing the novel's structure itself. In the book, the child and adult timelines constantly interrupt each other — an adult Loser's investigation in 1985 triggers a memory that cuts straight to 1958, over and over, so the past and present are always in conversation. The films can't do that once they're two separate movies released two years apart; Chapter Two uses flashbacks to the child cast, but it's a much blunter tool than the novel's constant back-and-forth, and it loses the way the book makes forgetting and remembering feel like the same act.

What "It" actually is, and the ending

This is the biggest content cut. In the novel, the Losers defeat It using the "Ritual of Chüd," and the climax reveals It as a fragment of an ancient cosmic entity called the Deadlights, with a whole mythology involving a benevolent counterpart force called the Turtle (Maturin) that helped create the universe. Chapter Two keeps the "true form is a giant spider" reveal but drops the Turtle and the cosmic mythology almost entirely — a choice Muschietti has said was necessary because the material read as too strange and hard to stage convincingly on screen, but one that leaves the film's ending as a more conventional monster fight than the novel's much weirder, more metaphysical one.

The films also change the mechanism of victory: the movie's Losers defeat It largely by verbally tearing it down and making it feel small (literally shrinking it by insulting it), rather than the book's ritual built on collective belief and unity. It's a punchier scene for a theater audience, but it trades the novel's central theme — that isolation is what makes people vulnerable, and that facing horror together is what beats it — for something closer to a standard blockbuster climax.

The sewer scene

The novel includes a scene, late in the 1958 timeline, where Beverly has sex with each of the boys in the Losers' Club, one after another, in the sewers beneath Derry — presented in the book as a ritual act meant to bind the group back together and give them a way out of the tunnels. It's one of the most widely criticized and debated passages in King's body of work, and the films cut it entirely, replacing it with nothing — the group simply finds their way out. This is the single most defended change among readers and critics alike, including from King himself, who has said in interviews he's not sure the scene would be included if he wrote the book today.

Characters combined, changed, or given more to do

• Mike Hanlon, the group's historian in the novel — the one who stays in Derry and remembers everything, and who researches It's history across the town's past — has his role significantly reduced. In the films, Ben becomes the group's researcher/architect figure instead, and Mike's arc is compressed and altered, a change some critics and readers have flagged as sidelining the novel's only Black protagonist from his most central function in the story.
• Henry Bowers, the Losers' human bully antagonist, survives the child timeline in the book and returns, briefly, as an adult threat in 1985 (escaped from a mental institution, manipulated by It one last time). The films kill Bowers off partway through Chapter Two instead, cutting that thread short.
• Audra, Bill's wife in the novel's adult timeline, and the subplot around her being nearly lost to It's influence, is dropped from the films entirely — Bill is single in the adult timeline instead, simplifying his arc considerably.

Pennywise himself

Tim Curry's 1990 miniseries performance is the version most people over 35 grew up with, but Bill Skarsgård's take in the Muschietti films is a deliberately different creation — more overtly monstrous and less charming, with a design (the ruff collar, the asymmetrical eyes, the drooling) built to be unsettling rather than seductive. Neither is more "book accurate" than the other; King's Pennywise shifts forms constantly and is described more through what it does than a fixed visual, so both performances are interpretations rather than direct translations.

Should you read the book if you've only seen the films?

Yes, if you want the stranger, more ambitious version of this story — the films are a solid, effective adaptation of the surface plot, but the novel's cosmic scope, its interwoven structure, and its more uncomfortable material (some cut for good reason, some just cut for runtime) make it a genuinely different experience, not just a longer version of the same one. Worth having both: the novel for the full story, and the two-film set for the version that introduced Pennywise to a new generation.

For the full breakdown of the novel's plot and what its ending means on the page, see our complete plot summary. For where It ranks against the rest of King's catalog, check our ranked list of King's best books.