This book is called a "classic horror." It was written in 1959, therefore, the style of writing is different than the way books are written today.
The first 100 pages (out of 175) tells about the characters involved. It isn't until after page 100 that anythings happens. It's more of a phsychological horror story.
If you like stories with lots of description and delving into the character's minds, you will like this book.