2001: A Space Odyssey (soundtrack) that shift slowly over time. This technique was pioneered in "Atmosphères", the only Ligeti piece heard in its entirety in the film. Ligeti admired Kubrick's film, but in addition to being irritated by Kubrick's failure to obtain permission directly from him, he was offended that his music was used in a film soundtrack shared by composers Johann and Richard Strauss. The Richard and Johann Strauss pieces and György Ligeti's "Requiem" (the Kyrie section) act as recurring motifs in the film's storyline. Richard Strauss' "Also Sprach Zarathustra" is first heard in the opening title which juxtaposes the Sun, Earth, and Moon.
Interpretations of 2001: A Space Odyssey machines". Kubrick was also confronted with the fact that, during the production of the film, the US and USSR had agreed not to put any nuclear weapons into outer space by signing the Outer Space Treaty. Alexander Walker in a book he wrote with Kubrick's assistance and authorisation, states that Kubrick eventually decided that as nuclear weapons the bombs had "no place at all in the film's thematic development", now being an "orbiting red herring" which would "merely have raised irrelevant questions to suggest this as a reality of the twenty-first century". In the Canadian TV documentary "2001 and Beyond",