from the Introduction:
The Newbie's Guide to Mystara is a netbook project written and compiled by members of the Mystara Mailing List and Mystara Message Board. It is designed to give players who do not know the world of Mystara a simple overview of the major nations in the Known World.
Mystara is the world where most of the Original D&D modules were set, and therefore is one of the oldest D&D settings alongside Blackmoor and Greyhawk. It is however much more then that and is in fact an entire setting that is loved by many, and we wish it to be shared with others. This guide is designed for primarily for players, although we advise DM’s to read through it to ensure that there is nothing that you wish to keep secret from your players in here.