You mean Follet's World Without End?. I enjoyed the book immensely . Post Apocalypsis can be other than physical cataclysm on eart, it can be THE Black Death as well. Ive read several in this genre and Follets is above most
Course theres Camu's "Plague" and "The Stand" . Well, theres several good plague books out there.
I don't think that's related to the movie I'm referring to. My "World Without End," was a 1950s movie, starring Rod Taylor, about a group of astronauts who end up centuries in the future, long after some cataclysmic war. The find a remnant of the human race living underground. I haven't seen it in years and it's never been transferred to DVD, but it was pretty good.