In seventeenth-century northern Europe, as the Aristotelian foundations of scientia were rocked by observation, experiment, confessional strife, and political pressure, natural philosophers came to rely on the printed image to fortify their epistemologies—and none more so than René Descartes. In Skepticism’s Pictures, historian of science Melissa Lo chronicles the visual idioms that made, sustained, revised, and resisted Descartes’s new philosophy. Drawing on moon maps, political cartoons, student notebooks, treatises on practical mathematics, and other sources, Lo argues that Descartes transformed natural philosophy with the introduction of a new graphic language that inspired a wide range of pictorial responses shaped by religious affiliation, political commitment, and cultural convention. She begins by historicizing the graphic vocabularies of Descartes’s Essais and Principia philosophiae and goes on to analyze the religious and civic volatility of Descartes’s thought, which compelled defenders (such as Jacques Rohault and Wolferd Senguerd) to reconfigure his pictures according to their local visual cultures—and stimulated enemies (such as Gabriel Daniel) to unravel Descartes’s visual logic with devastating irony. In the epilogue, Lo explains why nineteenth-century French philosophers divorced Descartes’s thought from his pictures, creating a modern image of reason and a version of philosophy absent visuality. Engaging and accessible, Skepticism’s Pictures presents an exciting new approach to Descartes and the visual reception of seventeenth-century physics. It will appeal to historians of early modern European science, philosophy, art, and culture and to art historians interested in histories that give images their argumentative power.