The book is a collection of horror short stories narrated in an unusual way. They are descriptions of the aftermath of tragic events, weird ruins and mysterious atmosphere and you have to piece together the clue to find out about the horrors that have occurred.
The same author of The Ritual
https://www.goodreads.com/book/show/51797060-wyrd-and-other-derelictions
You have me at Adam Nevill 👍. I loved The Ritual. I find the book way more terrific of the movie.
https://lemmy.world/post/4683928