This is the world introduced by the Player's Handbook. There isn't too much to say about it, other than it is limited only by your DM's mind. The Humanoid's Handbook introduces a multitude of new playable races, most of which are not found on all campaign worlds. They can all be found in the generic setting.
Almost all AD&D sites on the web are devoted to generic AD&D. It is the first world most players come into contact with, and it is my opinion that is is the best world to learn how to play in. Generic AD&D has no hostile slave trade (as in Dark Sun), no empires to run (Birthright), no mass numbers of undead (Ravenloft), no wars to fight, dragons to avoid (Dragonlance), no extra-planar monsters to fight (Planescape), etc.
There are no books in this world, but one might find that the books of the D&D series, the Forgotten Realms series, the Greyhawk series, or the new Mystara series. J. R. R. Tolkein wrote in a world called "Middle Earth." This is also a generic world.
There are numerous sites for a generic fan to visit. Here are some of the best:
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