Yes, it took me this long to see Deliverance (1972).
I thought the story originally appeared in The Atlantic Monthly, as this 1994 history of the magazine explains:
It was to The Atlantic Monthly that a little-known writer named James Dickey came when he had something called Deliverance that he wanted to publish.
But it’s not clear from what I can find on the web whether the magazine published the story. Perhaps the (at that time) affiliated publisher of the same name published the novel.
Wikipedia has a plot summary, including spoiler, although I wonder who hasn’t seen the movie besides me.
It’s solid, beyond the iconic scenes. Menace, with energy, and makes you wonder (if not think).