^ 2001 was based on Arthur C. CLarke's novel,
People keep getting this wrong.
2001 was not based on Clarke's novel. Clarke wrote the novelization of Stanley Kubricks's movie, while the movie was being produced. They collaborated certainly, but Clarke contributed material to an initial idea by Kubrick.
This is true, but my original point was that 2001 was based on ideas and premises that Clarke had written about for decades - the original versions of Childhood's End
and Against The Fall Of Night
are just two examples. The essential notions actually go back at least to Stapledon.