Oil! and the Upton Sinclair Adaptation There Will Be Blood
Paul Thomas Anderson adapted approximately the first 150 pages of Upton Sinclair's 1927 novel Oil! and discarded the rest. The novel is a 527-page chronicle of the California oil boom told through the eyes of a sympathetic son; the film is a 158-minute character study of a misanthropic father. The adaptation choices — what Anderson kept, what he cut, and what he invented — reveal as much about the film's intentions as the film itself.
Sinclair's novel is a political epic told through the son's perspective
Oil! follows Bunny Ross (James Arnold Ross Jr.), the idealistic son of a ruthless oil prospector, as he grows up amid the California oil boom, encounters socialism and labor organizing, witnesses the Red Scare, and grapples with his father's ethics. The novel is explicitly political — Sinclair, a committed socialist, used the oil industry as a lens for critiquing American capitalism, incorporating real events including the Teapot Dome scandal, World War I, and the rise of Southern California evangelicalism epitomized by Aimee Semple McPherson. (wikipedia)
The father in the novel, J. Arnold Ross Sr., is a secondary character — ambitious and morally compromised, but viewed through his son's sympathetic eyes. Sinclair was interested in how a decent young man navigates a corrupt system, not in the psychology of the corrupt system's architect.
Anderson inverted the novel's focus and abandoned its politics
Anderson's adaptation makes three decisive changes:
The protagonist shifts from son to father. H.W. exists in the film as a supporting character — a prop in Plainview's oil pitches, a victim of the derrick explosion, and finally a person who walks away. The novel's moral center becomes the film's structural accessory.
The politics are evacuated. Sinclair's novel devotes hundreds of pages to labor organizing, socialism, the Red Scare, and the political consequences of oil wealth. Anderson removes all of it. There are no union organizers in There Will Be Blood, no political parties, no organized resistance to Plainview's operation. The community of Little Boston has no collective agency — its members sell their land, attend Eli's church, and disappear.
The religious figure is reimagined as a structural mirror. Sinclair based his preacher character on Aimee Semple McPherson, a real figure in California evangelicalism. Anderson transformed this into Eli Sunday, a character whose function is not to represent a historical movement but to serve as Plainview's doppelganger — the same appetite for power expressed through spiritual rather than industrial means. (californiastudiesblog)
Anderson changed the title because the adaptation was too loose to claim the novel's name
Anderson was direct about the distance between his film and Sinclair's book.
"I was trying to find something that was 100 percent straightforward, old-fashioned storytelling." — Paul Thomas Anderson, IndieWire (2017)
He felt "there's not enough of the book to feel like it's a proper adaptation," so he changed the title. The film's credits read "based on the novel Oil! by Upton Sinclair," but the screenplay received a Best Adapted Screenplay nomination at the Academy Awards rather than Best Original Screenplay — a categorization that reflects the legal rights rather than the actual relationship between the texts. (wikipedia)
What Anderson kept from Sinclair is primarily texture, not plot
The elements that survive from Oil! into There Will Be Blood are situational rather than narrative: the California oil boom setting, the prospector who uses his son as a business asset, the corrupt preacher who mirrors the oilman's ambitions, and the raw physical danger of early drilling. Sinclair's specific plot — Bunny's political education, his encounters with socialism, his relationship with a labor organizer named Paul — is absent. The character named Paul Sunday in the film shares only a first name and a function (the person who sets the oil story in motion) with any figure in the novel.
Anderson's real source was not Sinclair's politics but his period research — the details of early oil prospecting, the texture of turn-of-the-century California, and the biographical material about Edward Doheny, the real oil baron on whom Sinclair partly based his characters. The film's screenplay is an original work wearing an adaptation's clothes.
Screenwriter Eric Schlosser secured the rights that made the project possible
Eric Schlosser — the investigative journalist who wrote Fast Food Nation — purchased the film rights to Oil! in 2004, before Anderson became involved. Schlosser's acquisition of the rights gave Anderson the legal framework to use Sinclair's setting and characters, even though the resulting screenplay departed radically from the source material. (wikipedia)