Samuel Pufendorf’s Of the Nature and Qualification of Religion (published in Latin in 1687) is a major work on the separation of politics and religion. Written in response to the revocation of the Edict of Nantes by the French king Louis XIV, Pufendorf contests the right of the sovereign to control the religion of his subjects, because state and religion pursue wholly different ends. He concludes that, when rulers transgress their bounds, subjects have a right to defend their religion, even by the force of arms. Pufendorf’s opposition to the French king does not demonstrate political radicalism. Instead, like John Locke and others who defended the concept of toleration, Pufendorf advocates a principled, moderate defense of toleration rather than unlimited religious liberty. Appearing at the dawn of the Enlightenment, Pufendorf’s ideas on natural law and toleration were highly influential in both Europe and the British Isles. As Simone Zurbuchen explains in the introduction, Of the Nature and Qualification of Religion is a major contribution to the history and literature of religious toleration. Samuel Pufendorf (1632-1694) was one of the most important figures in early-modern political thought. An exact contemporary of Locke and Spinoza, he transformed the natural law theories of Grotius and Hobbes, developed striking ideas of toleration and of the relationship between church and state, and wrote extensive political histories and analyses of the constitution of the German empire. Jodocus Crull (d. 1713/14) was a German émigré to England, a medical man, and a translator and writer. Simone Zurbuchen is Professor of Philosophy at the University of Fribourg, Switzerland. Knud Haakonssen is Professor of Intellectual History at the University of Sussex, England.