Looking for a definitive answer is out of place. Neither Kubrick's movie and Clarke's book (for 2001), nor Clarke's novels (2001 to 3001) can be considered consistent wholes regarding narration and story cohesion. There is no tiresome "canon" here. Kubrick privileged the symbolic aspect, making 2001 the impressive, timeless question mark that we know. In the context of the movie, clarifications had to be eluded. For instance, you probably know that for the "Dawn of Man" part of the movie, it was initially envisioned that pictures of the teachings of the monolith would be projected on its surface. Fortunately, the idea was abandoned. I don't think the monolith could have been sacralized (and therefore humorously desacralized, see
) in popular culture if it hadn't been such an enigma. Clarke, on his side, wanted to develop certain aspects of the story, and gave clearer explanations about HAL's motives, or the nature of the monolith. But Clarke's books have their discontinuities as well, and honestly, who cares ? He aknowledged such inconsistencies. From the Author's Note to 2061 : "Just as 2010: Odyssey Two was not a direct sequel to 2001: A Space Odyssey, so this book is not a linear sequel to 2010. They must all be considered as variations on the same theme, involving many of the same characters and situations, but not necessarily happening in the same universe. Developments since 1964 make total consistency impossible, as the later stories incorporate discoveries and events that had not even taken place when the earlier books were written." Rather than considering it a case of retroactive continuity, or "retconning" as they say, I would stress the "variations on the same theme" part. This thread can't be more than a playful conversation at the corner of the bar. Now personally, I like Kubrick's choices. HAL, and the monolith, stay in my mind as they are portayed in his movie. The path Clarke has chosen with his novels is too exhaustive for me. The books were good reads, but there are other novels, and especially novellas written by Clarke that I prefer.