But it was nonetheless based on a screenplay. And just because both came out in 1968 does not mean they came out at the same time. The book came out after the movie.
https://en.wikipedia.org/wiki/2001:_A_Space_Odyssey_%28film%29
Long before this movie came out, I had been reading Clarke's books and short stories. I based what I posted on what I know and also pulled some books to look at the publishing dates.
Yes, the book, which was published concurrent to the movie's opening, was the script, which was mostly based on several of Clarke's previously published stories. I stated that very clearly, in my posts.
And your quibble is?
I also saw the movie stone cold sober ( I've NEVER done any illicit drugs ) and the book explains a LOT of what goes on in the movie and is somewhat out there, with NO explanation...hence the book is NOT just an exact copy of the script.