Abstract: This article explores the relationship between the Enlightenment as a cultural and intellectual phenomenon and actual illumination in the long 18th century. Focused on street lighting in Paris, it nonetheless seeks to situate the French case in the broader context of developments in public lighting in the French provinces, Europe, and the Atlantic World. In the concerted effort to illuminate dark streets, the Enlightenment was operationalized in ways that bore fundamentally on commerce, sociability, and perceptions of progress, enlightened government, and enlightened space. At the same time, the attempt to illuminate formerly dark spaces generated reactions. A ‘dialectic of illumination’ was the counterpart to the dialectic of Enlightenment, fostering resistance to the new regime of light and its efforts to impose, through human ingenuity and instrumental reason, greater security and social control.