The radical Enlightenment was an intellectual and cultural movement that swept across Europe from the mid-seventeenth to the mid-eighteenth century, challenging theologically anchored belief systems and hierarchical conceptions of society. Recent historical and historiographical studies of this movement complicate the standard view of the Enlightenment as an emancipatory project that was advanced by freethinking modernists against traditionalists. In the revised account, the Enlightenment was a three-way struggle among conservatives, moderates, and radicals over the beliefs that then informed an entire gamut of social practices. While the more renowned and moderate mainstream of the Enlightenment sought to reconcile a burgeoning natural philosophy with revealed religion and monarchical or aristocratic tradition, proponents of the radical current made stronger claims that reason was the decisive standard for both natural and social-political orders. The radicals in this tradition included, most prominently, Baruch Spinoza, Pierre Bayle, and Denis Diderot, as well as less familiar Research ...