Sherlock Holmes and Dr. Watson meet Mulder and Scully. Jules de Grandin, physician and consultant for the Sûreté, has also been described as the occult Hercule Poirot, but I don't much care for Poirot myself so I'm going with the supernatural Sherlock instead. The Watson in this series of short stories by Seabury Quinn, published in Weird Tales beginning in 1925, is also a doctor, a New Jersey GP named Trowbridge, though he narrates the tales with more of Scully's skepticism than Watson's admiration sometimes.
And I had no idea these stories even existed until I read one of SF Signal's Mind Meld columns about a month ago, asking assorted authors for their recommendation of an underrated fantasy series. It was S. Andrew Swann who recommended de Grandin, and his remark that Quinn is to gritty noir urban fantasy what Tolkien is to grand high-fantasy epic got my attention. I'm a big fan of the Dresden Files, and I quite liked the X-Files when they weren't going overboard on the conspiracy (I liked the monster-of-the-week stories, so sue me), so of course I had to look up de Grandin.
Interlibrary loan is a wonderful invention, is all. The de Grandin stories were collected in the 1970s, but those paperbacks are long out of print now; my library couldn't find a copy of the first one anywhere in my state, and had to borrow it from a much larger library system in Dallas for me.
The Adventures of Jules de Grandin collects the first seven stories, including the one that introduces the characters of de Grandin and Trowbridge and what would become the standard setting for the stories, the town of Harrisonville, New Jersey, possibly the epicenter of more weirdness than any town since Arkham, Mass. Vampires, werewolves, zombies, mad scientists, curses, it's all here, and de Grandin is just the man who knows how to deal with it all.
There were 93 de Grandin stories in all. I'm tracking down the rest of them now.