Most famous for inspiring the Oscar-winning film There Will Be Blood, the novel Oil! chronicles the endeavors of James and his son James "Bunny" Junior in the corrupt oil business of southern California in the early 1900's. The book begins at the Watkin's family goat ranch, where the father-son dual is prospecting for oil. The father James attempts to dissuade Mr. Watkin's from beating his daughter by appealing to God, but the Watkin's son Eli accuses him of being a false prophet, claiming to be the real receiver of the Lord's "Third Revelation." Eli, Rachel, and their brother Paul become central characters in the story. Bunny becomes disillusioned with his father's unethical business practices and becomes involved with socialism through a classmate, Rachel. After his dad flees to avoid being subpoenaed by Congress, Bunny is swindled out of most of his inheritance by his dad's business associate. He thereafter decides to dedicate his life to social justice with Rachel, who he marries.

Published in 1927 by legendary muckraker Upton Sinclair of The Jungle fame, it inspired the creation of a film nearly a century later titled There Will Be Blood, which was nominated and awarded multiple Oscars. Both the film and the novel explore themes of corruption, greed, exploitation, and the consequences of unrestrained ambition.