Author Rosemary Jones claims to have written The Deadly Grimoire in response to reader demand for her to continue telling stories in the 1920s Arkham of H. P. Lovecraft and the 21st-century game designers inspired by him. Characters featured here and originating in the Arkham Files games include photo journalist Darrell Simmons and mail carrier Stella Clark.
The story is told by the actress Betsy Baxter (from Jones' previous Arkham novel Mask of Silver), who forms a friendship with the aviatrix Winifred Habbamock, the latter making her first appearance in Arkham literature outside of the games, as far as I know. Both of these protagonists are lady entrepreneurs of a sort, and the war-of-the-sexes framing from Mask of Silver is, if anything, intensified here, with an emphasis on "what the women know and the men forget" (226). There are some sympathetic male characters, including bookseller Tom Sweets.
Daniel Strange's cover art accurately suggests that this tale will lean into the "pulp adventure" flavor more than cosmic horror, and the narrative tone is often more comedic than horrific. I thought that Jones had cultivated a good sense of sustained menace in Mask of Silver, albeit perhaps more effectively for readers familiar with the jauniste horror of Robert W. Chambers. But that angle is pretty much dropped in this sequel, which instead orients to a feud between two Innsmouth families with some supernatural backstory. The more fortunate and less introspective narrator Betsy certainly gives this book a lighter tone than its predecessor.
In the appended acknowledgments Jones gives a shout out to Mildred Benson, and indeed, this book reads more like a Nancy Drew mystery adventure than it does pulp era weird horror, Lovecraftian trappings notwithstanding.