First adventure in the S (Special) series.
Originally written by Gary Gygax for the 1975 Origins 1 convention. In 1978, TSR published the module with a red monochrome cover for Advanced Dungeons & Dragons, First Edition.
The "killer dungeon" module tells the story of the evil wizard Acererak who became a lich and later a demi-lich which has transcended the need for a physical body other than its skull. Characters must survive deadly tomb traps and undead creatures in every corner.
A replica of this module was reprinted as part of the 1998 Return to the Tomb of Horrors box set.
Revised by Bruce Cordell it includes much of the original text, art, and maps with updated stats. Note that the map of the dungeon proper is updated and comes in two versions, keyed and unkeyed.
Tomb of Horrors was ranked the 3rd greatest Dungeons & Dragons adventure of all time by Dungeon magazine in 2004.
Anthologized in 1987 as part of S1-4: Realms of Horror (re-edited for campaign play), and again in 2013 as part of the S1-S4: Dungeons of Dread anthology.