[wolverine876]

That matches the history I know, generally. The original Basic, the 'Holmes Blue Book' by J. Eric Holmes, was indeed a much simplified restatement of OD&D, intended as an introduction. AD&D had many changes and much more material, though obviously it drew a lot on its predecessor.

I don't know that OD&D, even at the end of its publication run, offered nearly as much as AD&D. For example, where is the DMG? The modules?

However, while I know that OD&D had sparse rules as you say, and that the DM was expected to fill in the gaps and dungeons, where does it say that the characters didn't continue from adventure to adventure, from game to game?