Forgotten Realms
The "Campaign Set" (often referred to as the "Grey Box") was later released in 1987 as a boxed set of two source books ("Cyclopedia of the Realms" and "DM's Sourcebook of the Realms") and four large maps, designed by Greenwood in collaboration with author Jeff Grubb. The set introduced the campaign setting and explained how to use it, and reserved space on the map for SSI's Gold Box computer role-playing games set in the Forgotten Realms.
The Forgotten Realms Atlas
"The Forgotten Realms Atlas" is an indexed book which contains three-color maps from Forgotten Realms modules and novels. This includes large, small scale regional maps (one inch to two hundred miles), as well as detailed location maps and diagrams of story and scenario areas, and focuses on the Moonshae Isles, the Northwest lands near Waterdeep, and the Western Heartlands areas around Cormyr and the Dalelands. These large scale maps cover the areas detailed in Forgotten Realms game modules and novels that had been published before the "Atlas".