This book presents the first modern in-depth study of the theology of one of the most influential figures in post-Reformation Scotland, Samuel Rutherford (c. 1600-1661). Although much has been written over the years about Rutherford's political thought or about his nearly mystical piety, very little actually has appeared in print about his theology. Among those hwo have written Rutherford's theology in the past, none have done so in a comprehensive, systematic manner, and none have devoted any attention at all to examining Rutherford's Latin treatises. The current work seeks to fill both lacunae, by presenting Rutherford's theology, beginning with the doctrine of assurance, and by drawing chiefly upon what is arguably his magnum opus theologiae, the Examen Arminianismi. The Examen, which consists of lectures Rutherford delivered to his divinity students at St. Andrews University, is the closest thing he has to a proper systematic theology text. But because it is also a polemical treatise, aimed primarily against the Arminians, the Examen provides a context for us to engage not only with the seventeenth-century dispute over Arminianism, but also with the more contemporary debate of Calvin vs. the Calvinists.