A fantastically effective ghost story, as well as a neat little British mystery. Macardle writes very fluidly and fleshes out all he characters. Although the book has more detail and subplots than the wonderful movie starring Ray Milland and Ruth Hussey, you will enjoy reading if you have seen the film since Milland and Hussey (and the other actors) were so well cast.
I have read lots of ghost stories, but this one always remains on the top of the list, even ahead of The Haunting of Hill House, The Woman in Black, Hell House, and (barely) The Elementals. Hard to find a copy sometimes, but well worth the trouble.