• This article explores the use of Émilie Du Châtelet’s Institutions de physique as both an acknowledged and unacknowledged source for the Encyclopédie of Diderot and d’Alembert, and argues for Du Châtelet’s inclusion as a full participant in the philosophical conversations the Encyclopédie enacts. Widely considered a minor voice who entered the Encyclopédie solely through the mediation of Samuel Formey—a largely forgotten and conflicted encyclopédiste—new evidence generated using techniques developed in the digital humanities suggests that Du Châtelet was a much more central figure in the Encyclopédie’s engagement with the metaphysics of Leibniz and Wolff than previously thought.