The Forgotten Temple of Tharizdun

The Forgotten Temple of Tharizdun is an adventure module for the "Dungeons & Dragons" ("D&D") role-playing game, for use in the "World of Greyhawk" campaign setting. The module was published by TSR, Inc. in 1982 for the first edition "Advanced Dungeons & Dragons" rules.
Plot summary.
"The Forgotten Temple of Tharizdun" is set in the World of Greyhawk. This adventure starts with an incident from "The Lost Caverns of Tsojcanth". The player characters (PCs) follow a band of marauding norkers from the caverns, discovering the temple along the way. They must search through the dangerous mountain passes to find the norker lair inside the temple. The adventurers are drawn into the story by a gnomish community and travel to the temple. After battling their way in, the PCs explore the temple chambers, which contain mundane creatures and new monsters from the "Fiend Folio" supplement.
During their exploration, the characters may reach chambers of the temple in which religious rituals were performed, and risk insanity and death as they encounter remnants of worshipers of the imprisoned god Tharizdun. To progress further, the characters must enact portions of the rituals of worship of Tharizdun, traveling into an underground sub-temple, and magically opening an inner sanctum called the Black Cyst. Having advanced this far, the characters are likely to be driven insane, killed outright, or permanently trapped within the underground temple.
Publication history.
WG4 "The Forgotten Temple of Tharizdun" was written by Gary Gygax and published by TSR in 1982 as a thirty-two page booklet with two outer folders; there are no modules with the codes WG1-WG3. The module featured artwork by Karen Nelson. Nelson was an associate of Gary Gygax, and she was enlisted to assist in Gygax's goal of producing the adventure quickly, and outside the auspices of TSR's design department. The adventure is a loosely connected sequel to module S4 "Lost Caverns of Tsojcanth", and can be used with or without it. It is a combined wilderness and dungeon adventure set in the Southern Yatil Mountains, focused on a temple dedicated to the evil and insane Greyhawk god Tharizdun. A future work was promised to develop the plot from this adventure further.
Theme.
The thematic elements of nightmare and insanity bring Lovecraftian horror to "Dungeons & Dragons", and not for the first time. The concept of a trapped, malevolent god, intent upon the destruction of all that is, harkens to the dark and insane Great Old Ones of H.P. Lovecraft's fiction. In his comprehensive article on the topic of Lovecraftian influence on "D&D", "The Shadow Over D&D", James Jacobs says of "The Forgotten Temple of Tharizdun" and "Return to the Temple of Elemental Evil", "Tharizdun[...] obviously owes his pedigree to Lovecraft."
Reception.
Jim Bambra reviewed "The Forgotten Temple of Tharizdun" for "White Dwarf", and gave it 9 out of 10 overall. Bambra noted that "The Temple is brought to life excellently and contains plenty for players to think about, gaining entry requires good tactical play and an imaginative approach is needed to fathom out the Temple's hidden secrets."
Lawrence Schick, in his 1991 book "Heroic Worlds", criticized the module's cover as "the worst cover of any TSR "AD&D" module, a morass of colored blobs."
"The Forgotten Temple of Tharizdun" was ranked the 23rd greatest "Dungeons & Dragons" adventure of all time by "Dungeon" magazine in 2004. However, some have said that the final moments in the Black Cyst are anticlimactic.