Again, I'm not sure if this belongs here, but it fits as well as Flatland. Spaceland is a SF story by Rudy Rucker. It deals with the life of Joe Cube (stupid name, I know), and how it's changed when he's visited by a four-dimensional woman, named Momo. As corny as it may sound (and as weak as it's begining is) it turned out to be a very riveting piece of science fiction. It's really cool to get a glimpse of what it's like to be a three-dimensional being, in a four-dimensional Universe. In the story, Momo "augments" Joe Cube, so that he grows skin around his fourth-dimensional sides. It also causes him to grow an stalk, with a four-dimensional eye at the end, that reaches vout into the fourth-dimension ("vout" and "vinn" being the other two directions, besides up, down, south, north, west, and east), and looks back at the 3D world, from a four-dimensional perspective. From this perspective, nothing is hidden from Joe Cube - as everything is only three-dimensional, and thus completely open in the fourth-dimension. If you like "Flatland" and "Sphereland", you'll love "Spaceland".