The Known World
Dungeons & Dragons, or simply D&D, is the role playing system under which the majority of Mystaran adventures & campaigns take place.
to do: add notes on Mystara under the Holmes set, Moldavy set, RC, GAZ, etc.
Gawain's conversion project
Mystara 4e at the Piazza
Mystara under other (non D&D) systems (suggested link address for this?)
Rules section of Pandius