Several of Dick's stories have been made into films. Dick himself wrote a screenplay for an intended film adaptation of "Ubik" in 1974, but the film was never made. Many film adaptations have not used Dick's original titles. When asked why this was, Dick's ex-wife Tessa said, "Actually, the books rarely carry Phil's original titles, as the editors usually wrote new titles after reading his manuscripts. Phil often commented that he couldn't write good titles. If he could, he would have been an advertising writer instead of a novelist." Films based on Dick's writing had accumulated a total revenue of over US$1 billion by 2009.