Worth mentioning that the book and movie were written at the same time and influenced each other.

Originally, Kubrick and Clarke had planned to develop a 2001 novel first, free of the constraints of film, and then write the screenplay. They planned the writing credits to be "Screenplay by Stanley Kubrick and Arthur C. Clarke, based on a novel by Arthur C. Clarke and Stanley Kubrick" to reflect their preeminence in their respective fields. In practice, the screenplay developed in parallel with the novel, with only some elements being common to both. Kubrick originally planned a novel, first, with a film adapted from it. They also decided to release the same story as a novel.