After the release of "Switched-On Bach", Carlos was invited to compose the soundtrack of two science fiction films, "Marooned" (1969), directed by John Sturges, and "A Clockwork Orange" (1971) by Stanley Kubrick. When the directors of "Marooned" changed their minds about including a soundtrack, Carlos chose to work with Kubrick, as she and Elkind were fans of his previous films, adding: "We finally wound up talking with someone who had a close connection to Stanley Kubrick's lawyer. We suddenly got an invitation to fly to London." Before Carlos knew about the offer, she read the book and began writing a piece based on it named "Timesteps". A soundtrack containing only the film cuts of the score was released as "Stanley Kubrick's Clockwork Orange" in 1972, combining synthesized and classical music by Henry Purcell, Beethoven and Gioacchino Rossini with an early use of a vocoder. The album peaked the "Billboard" 200 chart at No. 146. Later that year, Carlos released an album of music not included in the final score titled "Walter Carlos' Clockwork Orange". Carlos later described the project as "a lot of fun ... a pleasurable venture".