This essay explores an aspect of Edgar Allan Poe’s short story “The Man of the Crowd” (1840) which has been largely neglected in literary studies until now: the motif of the gas lamp and the (cultural) consequences of artificial lighting. The bustling crowds in the streets of London at night would be unimaginable without gas lighting. The architecture of these new ‘lightrooms’ creates landmarks in the dark city which cause a reassessment of visual and cultural experiences. This gives rise to a new type of observer for whom the city, full of illusions, becomes the stage for an illegible crime story. By tracing the history of artificial lighting from the beginning of the nineteenth century, the following analysis of Poe’s short story explores the significance of the mobilization and mechanization of the new gaze through gas lighting and can therefore also be read against the background of the interdisciplinary field of material culture studies.