Start with high-confidence horror films books, then narrow by subgenre or adjacent topics.
The "supernatural" Book of Monsters, Spirits, Demons, and Ghouls
Alex Irvine, Alexander C. Irvine
World War Z
Max Brooks
Your Favorite Scary Movie
Ashley Cullins
Mazes of the Serpent
Roger B. Salomon
The Very Thirsty Vampire
Michael Teitelbaum
The Living Dead 2
John Joseph Adams
Hannibal Lecter
Brian Raftery
Scream With Me
Eleanor Johnson, Andi Arndt
We Are the Mutants
Kelly Roberts, Michael Grasso
Dracula
Bram Stoker
