I read Isaac Asimov's short story "Nightfall" many, many years ago. Didn't read the novelization by Robert Silverberg, but I did read the Silverberg novelization of "The Ugly Little Boy", which was very well done. Somewhere I have a non-fiction book by Silverberg on ancient civilizations that I'm half-way through. That was good too; I'll have to shovel through some other debris to find it. Oh, and into the !SciFi group with this!