This collection offers an innovative and fresh interpretation of Antitrinitarian and rational dissent in the early modern world. The central themes focus on the fierce debates surrounding Antitrinitarianism and Unitarianism that emerged from the Reformation and the lived cultures of these dissenting movements. The chapters take an interdisciplinary approach addressing ideas in context, their reception and appropriation, and the diverse and often conflicting visions of Christianity. Drawing on previously unused sources, many from Eastern Europe and often in inaccessible languages, this book challenges our understanding of dissent as marginal and eccentric and places it at the center of contesting convictions about the nature of religious reform.