In detailed studies the author analyzes important sections of the text and problems in Luther’s major work De servo arbitrio. This study in systematic theology is concerned with central issues which are controversial between Erasmus and Luther (among other things freedom of the will, ethics, theodicy, predestination and God’s hiddenness). In dialogue with classical philosophical and theological positions, especially with literary texts, it describes the strengths and aporias in Luther's assertive, confessional, pugilistic theology.