Useful books that i found at my local library
Film Theory An Introduction - Robert Stam

Anatomy of Film - Bernard F. Dick

Thrillers - Martin Rubin

Useful books found from http://www.bfi.org.uk/filmtvinfo/library/publications/16+/pdf/horror.pdf
The zombie that ate Pittsburgh: the films of George A. Romero - Paul R. Gagne

America Horror: essays on the modern American horror films The living and the undead: from Bram Stoker’s Dracula to Romero’s Dawn of the Dead - Gregory A. Waller

Dreadful pleasure: an anatomy of modern horror - James B. Twitchell