Realms of Horror

Realms of Horror is a "supermodule" compiled from the S–series of "Dungeons & Dragons" modules, which were four distinct "Advanced Dungeons & Dragons" 1st edition adventure modules, designed for use by Dungeon Masters as pre-made scenarios that are ready to be played with minimal preparation.
Plot summary.
"Realms of Horror" contains four scenarios compiled from modules S1 through S4, which have been slightly revised to form a connected campaign.
Publication history.
The "S," standing for "Special," in the series' name is the first part of the alphanumeric code used to indicate related modules. The four S–series modules were released over the four-year period between 1978 and 1982.
S1-4 "Realms of Horror" was written by Gary Gygax and Lawrence Schick with Wm. John Wheeler, with a cover by Larry Elmore, and was published by TSR in 1987 as an 80-page book, a 48-page art booklet, a 16-page map booklet, and an outer folder.
Reception.
All four of the modules were in "Dungeon's" 2004 article, "The 30 Greatest D&D Adventures of All Time"