It's a shame to have a mostly negative review as my first on this site, but that's the way it has to be unfortunately.
The first story, the titular "Ghost of Longthorn Manor" started off the whole book really well, with a nice twist in the tale, albeit one you could guess fairly early on.
However, the rest of the collection was rather disappointing by comparison. The supernatural happenings of the tales lacked, for my taste, sufficient explanation or resolution. I understand the desire to leave a little mystery and not explain everything, but a lot the stories just ended with basically "the protagonist succumbs to the paranormal thing despite them somehow narrating the story in the first person".
The language used also bothered me, although I will acknowledge this is probably down to my own personal pickiness. Some of the stories seemed to be set in the US and some were clearly set in England, but the stories supposedly told by American characters used a lot of British slang, while those apparently with English characters used American phrases and idioms. This, for me, was very jarring, and diminished the atmosphere of the tales.
Additionally, I found the 'twist' of the final story "The Writer", which I think was supposed to be creepy and thought-provoking, to just be laughably cheesy, almost like something from a parody.
Perhaps other horror/ghost story fans might enjoy this collection more, but it wasn't for me, sadly.