Feb 10
"As a member of a bold party of adventurers, you and your associates have trekked far into what seems to be a whole underworld of subterranean tunnels -- arteries connecting endless caves and caverns which honeycomb the foundations of the lands beneath the sun." (Dave Trampier back cover art from AD&D module D3: Vault of the Drow by Gary Gygax, TSR, 1978). This image also appeared in some ads for the module.
Here Gygax continued to use the word "underworld" to describe the otherworldly realm of deepest dungeons, the same term he originally used for all dungeon environments in OD&D in 1974. Douglas Niles introduced the term "Underdark" in 1986 in his Dungeoneer's Survival Guide.
