Why are audiences drawn to horror films? Answers to that question include everything from a need to experience fear to a hunger for psychotherapy. This critical text proposes that the horror film's primary purpose is to present monsters, best understood as deformed and destructive beings. These monsters satisfy the audience's desire to know the extremities of being, in particular those beings too fantastic and dangerous to know in real life. The text illuminates many aspects of the horror film genre, including epistemology, ethics, evaluation, history, monster taxonomy, and filmmaking techniques.