In the book Dark Dreams, author Charles Derry conceived horror films as focusing on three broad themes: the horror of personality, horror of Armageddon and the horror of the demonic.[18] The horror of personality derives from monsters being at the centre of the plot, such Frankenstein's monster whose psychology makes them perform unspeakable horrific acts ranging from rapes, mutilations and sadistic killings.[18] Other key works of this form are Alfred Hitchcock's Psycho, which feature psychotic murderers without the make-up of a monster.[18] The second 'Armageddon' group delves on the fear of large-scale destruction, which ranges from science fiction works but also of natural events, such as Hitchcock's The Birds (1963).[18] The last group of the "Fear of the Demonic" features graphic accounts of satanic rites, witchcraft, exorcisms outside traditional forms of worship, as seen in films like The Exorcist (1973) or The Omen (1976).[19]