The premise of this article is that Montesquieu, while seen as an Enlightenment thinker who contributed centrally to the development of the social sciences before the period of discipline formation in the nineteenth century, is generally appreciated in only the vaguest of terms. To the degree that he has been seen as a social theorist rather than as a belletrist or a political writer, scholars have had to amputate major sections of his masterwork, De l'esprit des lois (1748). In so doing, they have tended to give false or at least only partial readings of a work whose author insisted must be read as a whole. This article proceeds in an unorthodox fashion—at least for a historian—through a reading of De l'esprit des lois against Claude Lévi-Strauss's Les structures élémentaires de la parenté (1949). Through this parallel reading, I establish that Montesquieu's treatment of inheritance bears a remarkable homology with Lévi-Strauss's treatment of incest in Les structures élémentaires. These authors saw their respective objects—the incest taboo, in one case, and inheritance law, in the other—as fundamental to regulating sociability itself. This technique offers a more unified reading of De l'esprit des lois and, in so doing, reassesses Montesquieu's contribution to modern social theory. From a methodological point of view, I am hoping to interest my readers in an alternative way of reading historical texts: juxtaposing texts or corpora that do not have the clear genetic links between them that are generally highly valued by historians. This is an example of what Robert B. Pippin has called “interanimation” and what I have elsewhere likened to the painterly technique of simultaneous contrast.