The classic "Gray Box" for 1st Edition D&D.
From the Back of the Box:
Within this box is everything needed to visit the fabulous Forgotten Realms. The 96-page player's book contains entries on all known areas, cities, people, and things, presented in alphabetical order. Numerous maps outline the more well-known cities and lands. The 96-page DM's book contains all the information pertinent to running a campaign set in this fantasy world, from how to bring existing characters into the Forgotten Realms to two complete introductory mini-adventures to a listing of known magical texts and the magics contained therein. Four full-color maps show the entire lands and details of the more well-known areas. Adventuring rules specific to the Forgotten Realms have been included.