Carnacki, the Ghost Finder

Thomas Carnacki investigates the impossible for a living: haunted houses, cursed manuscripts, and things that howl behind sealed doors, approaching each case with the mind of a detective and the equipment of a scientist — alongside older, stranger defenses drawn from an ancient text called the Sigsand Manuscript. Some of his cases turn out to be elaborate frauds; others are unmistakably, terrifyingly real. First published in the 1910s, William Hope Hodgson's linked stories helped invent the "occult detective" as a genre in its own right, a direct ancestor of every ghost-hunter and paranormal investigator in fiction since.