By adapting, for the first time, methodological insights from the scholarship of historical entanglement (l'histoire croisée) to the study of the Enlightenment, this book provides a new interpretation of the European republic of letters from the late 1600s through the 1700s by focusing on the lived experience of the long-neglected Catholic theologian, historian, and contributor to Diderot's , Abbé Claude Yvon. The ambivalent historical memory of Yvon, as well as the eclectic and global array of his sources and endeavors, Burson argues, can serve as a gauge for evaluating historical transformations in the surprisingly diverse ways in which eighteenth-century individuals spoke about enlightening human reason, religion, and society. Ultimately, Burson provocatively claims that even the most radical fruits of the Enlightenment can be understood as the unintended offspring of a revolution in theology and the cultural history of religious experience.