After Eric Schlosser finished writing "Fast Food Nation", reporters kept asking him about Upton Sinclair. Although he had read Sinclair's "The Jungle", he did not know about his other works or anything about Sinclair himself. He decided to read most of Sinclair's works, and eventually read the novel "Oil!", which he loved. Schlosser, who found the book to be exciting and thought it would make a great film, sought out the Sinclair estate and purchased the film rights. He thought that he would try to find a director who was as passionate about the book as he was, but director Paul Thomas Anderson approached him first.