Accepting the common lay definition of nightmare as any form of upsetting, dreamlike cognition occurring in the midst of sleep, the author argues for a classification of nightmares that would be based, not on physiological findings, but on what the upsetting nocturnal occurrence turns out to mean to the dreamer. Three types of nightmare identified on this basis are illustrated through dream sequences from classic Hollywood movies and amplified by clinical examples: (1) the dream that symbolizes the next stage of life as unusually daunting, (2) the dream that exposes the shadow of another person in a shocking way, and (3) the ‘empathy dream’, in which the dreamer experiences directly the anxieties of another subject. It is suggested that the accurate interpretation of a particular upsetting dream depends upon which type of nightmare the dream turns out to be.