variations on an idea

I read a whole lot of science fiction, speculative fiction, whatever you want to call it. I've just read Kingdoms of the Wall by Robert Silverberg, and it's put me in mind of a story I made up, a mode of analysis to explain to my housemate the relationship between a completely different set of books.

( SPOILERS for Kingdoms of the Wall, Moon-Flash, The Case of the Toxic Spell Dump, Operation Chaos, Magic, Inc., The Call of the Wild, Heart of Darkness )