Book and movie differences, one work at a time
Book and film differ in 4 places, and this site measures all 4 separately: plot, character, voice and theme. A film can keep almost every event of a novel and still lose its meaning, as the 1931 Frankenstein does by taking speech away from the creature. A film can throw out half the events and keep the meaning whole, as Jaws does in 1975. One question, "is it faithful", produces one flat answer. Four questions produce a description, and a description is what a reader arriving from a book page or a film database actually wants.
The 4 questions asked of every case file
The 4 questions come in the same order on every case file, because the order is itself an argument: what happens is the easiest thing to carry across, and what a book means is the hardest.
- Plot. Which events survive, which are cut, which are invented, and whether the ending arrives by the same route.
- Character. Who lives, who dies, who changes age, profession or sympathy, and who exists only on one side of the crossing.
- Voice. Who is telling this, and from where. First person, retrospective narration, unreliable narration and interior monologue have no automatic screen equivalent, so voice is where most films travel furthest without meaning to.
- Theme. What the work is finally about. A film can reverse a novel's argument while reproducing its scenes, which is the single most common form of infidelity and the least often noticed.
Voice is the axis that catches people out. Readers describe a film as unfaithful and then struggle to name a changed event, because what changed was the position they were reading from.
How far a film travels, and what the distance scale does not measure
Distance is recorded here as a percentage on each axis, in 4 bands, and it is a description of movement rather than a mark out of 100.
- Under 25 per cent, keeps. The film reproduces the book's version of that axis with local trims.
- 25 to 50 per cent, adjusts. The film compresses, reorders or reassigns, but a reader recognises the shape.
- 50 to 75 per cent, rebuilds. The film constructs its own version out of the book's materials.
- Above 75 per cent, replaces. The film substitutes something new and keeps the title.
The case files, measured
The case files below each take one novel against the film or films made from it, and the bar records the total distance travelled across all 4 axes.
| Work | Book | Film | Distance |
|---|---|---|---|
| The Exorcist | 1971 | 1973 | |
| The Martian | 2011 | 2015 | |
| Bridge to Terabithia | 1977 | 2007 | |
| The Great Gatsby | 1925 | 2013 | |
| Coraline | 2002 | 2009 | |
| Divergent | 2011 | 2014 | |
| Dune | 1965 | 2021 and 2024 | |
| It | 1986 | 2017 and 2019 | |
| The 9th Life of Louis Drax | 2004 | 2016 | |
| Jurassic Park | 1990 | 1993 | |
| Jaws | 1974 | 1975 | |
| The Hobbit | 1937 | 2012 to 2014 | |
| Frankenstein | 1818 | 1931 | |
| Forrest Gump | 1986 | 1994 | |
| Remarkably Bright Creatures | 2022 | open | not yet measurable |
Two rows explain the range. Peter Jackson's Hobbit films, released between 2012 and 2014, turn one children's book of roughly 300 pages into 3 features, drawing on Tolkien's appendices and inventing characters, Tauriel among them, who have no source at all. Mary Shelley's creature reads Paradise Lost and argues its own case for 3 volumes; James Whale's 1931 film makes it mute, and popular usage has been calling the creature Frankenstein ever since.
Why the best adaptations are rarely the closest ones
The best adaptations are rarely the closest ones because a novel and a film fail in different places, and a good director cuts where the novel was carrying weight the camera cannot lift. Jaws is the clearest case: Steven Spielberg and his collaborators removed the adultery subplot, the organised-crime pressure on the mayor and most of the town politics from Peter Benchley's 1974 novel, and what was left was 3 men, a boat and an animal.
The reverse failure is more common. Gabor Csupo's 2007 Bridge to Terabithia stages the imagined kingdom that Katherine Paterson's 1977 novel deliberately leaves inside the children's heads, which shifts the book from a realist story about grief towards fantasy. Baz Luhrmann's 2013 Great Gatsby adds a framing device in which Nick Carraway writes the story from a sanatorium, importing a narrator the novel has by default and a diagnosis it never gives him. Neil Burger's 2014 Divergent reproduces the events of Veronica Roth's 2011 novel and drops the first-person present tense that made them feel immediate. All 3 are cases of high plot fidelity with heavy movement on voice.
The 2 files that test the scale
The 2 files that test the scale are It and Remarkably Bright Creatures, and they sit at opposite ends of it: one novel has 2 competing screen versions to be measured against each other, the other has no screen version at all and so has nothing yet to measure.
King's 1986 novel alternates between the children of 1958 and the adults of 1985 chapter by chapter, so memory and event occupy the same page.
Andy Muschietti's 2017 film cuts the adult timeline out entirely and returns it in 2019 as a separate feature, so the braid becomes a sequence.
Shelby Van Pelt's Remarkably Bright Creatures, published in 2022, is the open file. A screen version has been announced and nothing has been released, so there is no distance to measure yet, only a prediction worth recording in advance: the novel gives several chapters to a giant Pacific octopus who thinks in the first person, and that is precisely the kind of voice that adaptations either solve with narration, solve with performance, or quietly delete.