If you wanted to solve a crime in late Victorian London, you called Sherlock Holmes. If you wanted to solve a spooky crime in Edwardian London, you called Thomas Carnacki, the ghost finder.
Between 1910 and 1912, William Hope Hodgson wrote a series of short stories in The Idler and The New Magazine featuring his supernatural detective Carnacki. Based on the aforementioned Mr Holmes, Carnacki's brief was to investigate supposed haunting–usually ones with a suitably grisly facet to them. These stories, which where collected in 1913 and in an expanded edition in 1948, follow a rigid formula. The narrator of the story and three friends gather at Carnacki's London home for dinner followed by the detective treating them to an exciting tale from his casebook. Everything is more or less wound up at the end and Carnacki sends them all home.
The variety comes in the cases themselves. Some are genuine affairs of outright demonic hauntings by malevolent supernatural beings. Others are fakes perpetrated for one reason or another and some are a weird combination where the fakers unwittingly collide with the eldritch. The stories do have something of a repetitious quality with Carnacki forever letting off the flash of his camera or hiding in the protection of his "electric pentacle", but what makes them work is the uncompromising atmosphere of terror that Hodgson brings to the stories. Carnacki is an honest enough character to admit when he's scared out of his wits, even when it turns out to be a trick, and Hodgson's descriptions of what is like to be sitting in the dark while something paces and pants around the room is truly frightening. This is enhanced by Hodgson's talent for finding spine-tingling throwaway descriptions of his horrors that cunningly seed the reader's imagination. This is not a book to finish just before bedtime unless you've left on all the lights and are absolutely certain that the noise you heard after turning in really is just your daughter's pet mouse running in its wheel.
Otherwise, it can be a very uncomfortable night.