An interesting early occult detective is Thomas Carnacki by English author Willam Hope Hodgson (1877-1918).
Hodgson wrote several works of horror, science and fantastical fiction, as well as nautical tales, and his Carnacki works are among his best known and most readable. Hodgson was an inspiration to later authors such as H.P. Lovecraft, and Carnacki is one of the first occult detectives.
Carnacki appeared in nine short stories. Six appeared between 1910 and 1912 in British magazines such as The Idler and The New Magazine. Three more were found and published posthumously.
The first complete collection of stories was the collection from Arkham House in 1948 titled “Carnacki the Ghost-Finder.” One can easily find reprints of these stories, but the definitive collection should be coming soon from Sam Gafford who is a researcher on Hodgson and has recently published a journal called Sargasso devoted to Hodgson and his works.
All the stories are somewhat formulaic. All are told in first person by an associate of Carnacki. The plot of the stories are basically told by Carnacki after dinner with a group of four friends that includes the narrator. Carnacki is basically regaling them with his latest case. In about half the cases, it turns out there is a mundane and non-supernatural cause. But the rest?
Carnacki uses his invention, the “Electric Pentacle,” to protect himself from supernatural forces. As the pentacle is usually done with candles, Carnacki’s can be seen as an modern updating with electricity. Also used is a fictional ancient text, the “Sigsand Manuscript,” from which Carnacki uses certain rituals and incantations to protect himself.
For anyone wanting to see how occult detectives have developed, he is one to check out. It’s actually strange that until fairly recently, no one had done any new Carnacki stories. It seems only in the last few years have there been several. He has appeared recently in the “Tales of the Shadowmen” collections, sometimes with other occult detectives. This kind of reminds me of the teamup of various DC Comics occult detectives referred to as the “Trenchcoat Brigade.” I hope we see further such stories.
“No. 472 Cheyne Walk” (the name is taken from Carnacki’s address) is a collection of stories by A.F. Kidd and Rick Kennett. While the book had a limited run, you can get it in ebook format. “Carnacki: Heaven and Hell” by William Meikle is another new collection of stories. Sadly, I have yet to get any of these.
A very recent collection of new stories edited by Sam Gafford is “Carnacki: The New Adventures.”
Guy Adam included Carnacki in his new Sherlock Holmes novel “Breath of God,” which also included occultist Aleister Crowley.
As noted, its fairly easy to find the original stories. So check out Carnacki!