Carol (2015) is the film adaptation of Patricia Highsmith's 1952 novel previously titled The Price of Salt, written under the pseudonyum Claire Morgan. When Bloomsbury republished the book in the 1990s, they changed the title to Carol. Much speculation has arisen over the meaning of the story's original title The Price of Salt and why Highsmith chose to change its title.  At a New York City panel discussion on November 17, 2015, Phyllis Nagy, the writer of the screenplay, who was friends with Highsmith, offered some insight into the title's significance and Highsmith's motivations.

According to Nagy, Bloomsbury Publishing wanted Highsmith "to finally claim the novel as her own and...because it had been known under the pseudonym of Claire Morgan she felt it was more appropriate to have a clean start...[Highsmith] always wanted to title it 'Carol' and so she did."  

Highsmith later commented that The Price of Salt had come from something she was thinking of in the Bible. Nagy states that it is a biblical "reference to Lot's wife, the story of Lot's wife and the price of literally turning back." Like Lot's wife, Hagar, Carol (played by Cate Blanchett) can not return to her former life, pre-Therese, and a sham marriage that has long forced her to deny her true desires. Instead, she makes the most difficult decision a mother could make - to give up custody of her daughter - rather than become a shell of a person and let her real self disintegrate into a pile of indistinguishable grains of salt. At the moment of her decision she asks, "What use am I to her if I’m living against my own grain?” Alternatively, Joan Schenkar in her book The Talented Miss Highsmith: The Secret Life and Serious Art of Patricia Highsmith contends that it is more likely Highsmith "was invoking a biblical reference to another work she had once taken to heart - the Gospel text Andre Gide inserted into The Counterfeiters, his novel about the transgressive love of adolescence: 'If the salt have lost its flavor wherewith shall it be salted? - that is the tragedy with which I am concerned.'" (MacMillan 2010, pg. 272) 

Highsmith chose the title Carol because, Nagy explains, "Pat herself was Therese and the object of her desire wasn't herself, luckily, it was someone else." Written from the perspective of Therese Belavit (played by Rooney Mara), a young New York shop girl, the book is "basically an interior monologue of her thoughts," Nagy said in an Indiewire interview. "In the book, Therese is Pat’s alter ego, so she isn’t a character — she’s the voice of an author." 

Highsmith has admitted "a specific inspiration" for the story and for the character of Carol: a "blondish woman in a fur coat," whom Highsmith once encountered while working at Macy's where the woman bought her daughter a doll for Christmas. Highsmith confessed that she took the woman's address from the sales slip and on Highsmith's day off, she took a bus to New Jersey to spy on the woman. Highsmith also drew inspiration for Carol's character from one of Highsmith's former lovers, Virginia Kent Catherwood, a Philadelphia socialite whose divorce in the 1940s had provoked gossip columnists in New York into a state of "scandalised delirium with its lesbian intrigue." Catherwood lost custody of her child as a result of a recording made of her and a female lover was used in court against here. Highsmith mined this detail for the story "making the love affair between Carol and the younger, mute-with-longing Therese (based on Highsmith herself) all the more perilous and poignant," Jill Dawson writes in "Carol: the women behind Patricia Highsmith's lesbian novel" for The Guardian.

Carol arguably represents the object of Patricia Highsmith's own desire. She is a vital, glamorous, self-assured woman who pursues her own inner wants and impulses, refusing to be tethered by social custom and forced to live against her grain. She is not Carol (Insert Married Surname or Maiden Name); she is not Carol the Lesbian Divorcée Mother in the 50s; she is defined by no category. She is a particular, unique person who interests and moves us, just as the film succeeds for not being about anything more or less than two people who happen to fall in love with each other. She is Carol.