The book ending is a lot more SF. I've not read it since before the film came out, actually. I should read it again.
I'm currently rereading Childhood's End. It was written in 1953 but takes place (the beginning anyway) in the mid-70s. Then it's 50 years until the next major part of the book, so mid-2020's.
The Jedi Master
It's been a while since I saw the series and read the novel, so I can't remember if the same reason for humanity's reaction to the Overlords is given at the end.
