In many ways, MUDs like FurryMUCK and LambdaMOO operate as books do, especially since they are completely textual. The first MUDs were simply on-screen books that led users through a narrative, with the occasional opportunity to fight one-on-one with other players. Traditionally, the only experience requiring the reading of text for so long at one sitting is found in bound books. For this reason, MUDers often carry over concepts from reading and writing physical texts into MUD space. But the assumptions associated with the reading of physical books, like the assumptions for face-to-face communication, do not transfer perfectly into screen-based, or hypertexts. In fact, as New Mexico State University professor Steven Bernhardt, one of the pioneering researchers of hypertext, notes: "Thinking, working, and composing in the new medium of hypertext has a grammar all its own, a grammar with a steep learning curve and challenging new conceptual structures" (Bernhardt, in press), adding that, "We are in a state of rapid evolution, with heavy borrowing on the history of text on paper, applied sometimes appropriately and sometimes inappropriately to the new medium" (Bernhardt, College Comp., 151). In the medium of the screen, text is both physical (letters on the screen) as it is in books, and fleeting and ethereal like speech, again causing a strange middle-ground between and written and oral sensibilities, and new freedoms and constraints on language.