An elderly man comes into a scholarly library and asks for a certain Hebrew commentary, but the assistant cannot get to the book and experiences some disturbing things. The book appears to be haunted...
Mr. Garrett is the hero of this story and the first to be haunted, but there's a bit of a difference here from many MRJ stories; he is not the focus of the attack at all, and in fact his terrifying experience protects an innocent person. The ghost is not a nice one at all, but it is protecting someone. Perhaps it's trying to atone for sins committed in life? Maybe it's a Marley-esque ghost, or it can't rest until it gets rid of the villain.
The Tractate Middoth is a real book of Hebrew commentary. It's the sort of thing only a very serious scholar would consult, I think.
Finally, in case you were wondering what Piccadilly weepers could be, here is a lovely photo for you. They're the sideburns worn long (sometimes very long, from some of the photos I saw!), and the mustache is optional. This style is also known as the Dundreary. Both names seem to me to be on the melancholy side, don't you think?