This book considers different forms of voluntarism developed from the thirteenth to eighteenth centuries. By crossing the conventional dividing line between the medieval and early modern periods, the volume draws important new insights on the historical development of voluntarism. Voluntarism places a special emphasis on the will when it comes to the analysis and explanation of fundamental philosophical questions and problems. Since the Middle Ages, voluntarist considerations and views played an important role in the development of different theories of action, ethics, metaethics, and metaphysics. The chapters in this volume are grouped according to three distinct kinds of voluntarism: psychological, ethical, and theological voluntarism. They address topics such as the threat of irrationality as the standard objection to voluntarism, incontinent actions and their explanation, the nature of the will as rational appetite, the relationship between intellect and will, the implications of conceptions of the will for political freedom, and the relations between divine freedom and the modal status of eternal truths. The chapters not only consider towering figures of the Middle Ages—Thomas Aquinas, Henry of Ghent, William of Ockham, Francisco de Vitoria—and early modern period—René Descartes, Thomas Hobbes, Gottfried Wilhelm Leibniz, Samuel Pufendorf—but also engage with less well-known figures such as Peter John Olivi, John of Pouilly, Catharine Trotter Cockburn, and Christian August Crusius. Varieties of Voluntarism in Medieval and Early Modern Philosophy will appeal to scholars and advanced students working in medieval philosophy, early modern philosophy, the history of ethics, and philosophy of religion.