By the Falls, by Harry Harrison

We have all heard of the story of Plato's Cave, at least if we have had an intro to philosophy class. Persons chained in a cave can see shadows of things outside, and try to discern what is going on outside by the shadows. Such is the premise of Harry Harrison's 1970 Nebula nominee, By the Falls. Instead of a cave, there is a great waterfall, basically the edge of the earth. But the protagonists in the story are halfway down the massive falls, viewing it from the side. Harrison provides a great description of the falls' power. The reporter who comes to interview a man living beside the falls sees things in it, and tries to figure out what is going on at the top. Very interesting stuff, it's worth checking out.