Dracula (1958)
Hammer's 1958 Dracula made the vampire physical, sexual, and bloody. Christopher Lee plays Dracula, and the performance redefined the role.
Jimmy Sangster wrote The Curse of Frankenstein, Dracula and The Brides of Dracula, the scripts that established Hammer as a horror studio and defined its approach for a decade.
His innovation was structural. The Universal films had treated the monsters as tragic; Sangster made Frankenstein himself the villain, ruthless and charming, which gave Peter Cushing something far more interesting to play.
He later wrote thrillers for Hammer in the Psycho mould, and directed several films for the studio as well.