This is old news to some, but I thought I ought to make mention of it here nonetheless. An old article by Gary Gygax, entitled "How to Set Up Your Dungeons & Dragons Campaign -- And Be Stuck Refereeing It Seven Days Per Week Until the Wee Hours of the Morning!", was recently unearthed. It appeared in a European wargaming fanzine called Europa in the April 1975 issue. Gary's article appears on pages 18-20 and is quite fascinating from a historical perspective, both in terms of his discussion of how he designed his own campaign and because it's from a very early period, before D&D's popularity reached its eventual heights. Gygax also describes, albeit sketchily, the 13 levels of the original Castle Greyhawk and their inhabitants.
The other thing of interest here is that the article is clearly written by "Gamer Gary," as opposed to "TSR Gary." That is, it's written from the perspective of one gamer to another rather than being full of pontifical pronouncements by someone looking to sell you new products. Gamers who entered the hobby after 1979 or so probably have little to no experience of "Gamer Gary" and even I sometimes forget about his existence. It's nice to be reminded of him from time to time and this short article does that very well, in addition to its other more obvious uses.