Thinking back to the Eighties the unassuming paperback stared at me from the spinner rack in Dobson's Tobacco Mart in '87. The cigar & smoke shop was a head shop if there ever was one on the Massachusetts Connecticut border. There was a smattering of horror paper backs & the occasional gaming product. We used to stop there on our way back from making runs up to New York state. 'The Case of Charles Dexter Ward' was of particular interest to me. This paperback was under the Del Rey imprint.
'The Case of Charles Dexter Ward' is particularly important if the dungeon master is going to run 'Driven young antiquarian Charles Ward investigates his ancestor, the necromancer Joseph Curwen, and gets more than he bargained for.' routine. The novella could easily be turned into an epic Sword & Sorcery campaign with little issue. There are a bushel of monsters , corpses, ruins at midnight and haunted labyrinths.
What really makes 'The Case of Charles Dexter Ward' so pivotal for a Sword & Sorcery dungeon master is the fact that there's a whole cloth history of a group of secret Illuminati style necromancers who are raising the dead for nefarious purposes. The implication is that this organization exists across the world. Their resurrecting is horrific & deadly its perfect as an add on for 'A0-A4 Against The Slave Lords' By David "Zeb" Cook, Allen Hammack, Harold Johnson, Tom Moldvay as a sort of back handed adventure subplot.
The necromancers of the slave lords are resurrecting old wizards & rivals to pry their secrets from them then send them back to the grave or turn them into mindless undead travesties or guardians. This leads me back to some of the NPC's that are in the Rogues Gallery book, they make excellent fodder for this angle of the Slave Lords.
Hell several of the NPC wizards, clerics, etc from the Advanced Dungeons & Dragons Rogues Gallery might be victims of this group of necromancers & black wizards. What really sets this off the chain is the idea that this organization in 'The Case of Charles Dexter Ward' might be operating both in the 1920's & the world of Greyhawk. In fact Count Dahlvier the master of Castle Dahlvier and head of the hexad of liches, might be perfect as an addition to this Lovecraftian cabal.
Because numerous cross Lovecraft references the whole cloth of the 'Case of Charles Dexter Ward' is great to spin as the DM wants or needs for his players. And I think this is one of the novella's strengths is how adaptable these stories are.
This is also one of the strengths of the old school modules as well. They flex & bend to the dungeon master's needs & wants for his or her players. If you wanted to really do the player's heads in one of the wizards of the party might be a member of such a cabal sent to spy on the player's PC's.