The Islamic prophet Muhammad initiated a theological program in theocratic form. The Qur’an challenges Christians and Jews in many ways and invites them to take a stance. This is why an explicitly theological response is legitimate and necessary. This book draws on current scholarly research on Islam and discusses the sources of the Qur’an, the fundamental features of its relationship with Judaism, and its perception of Jesus. This leads to a realistic assessment of Islam and stimulates a renewed Christian self-understanding. The fourth chapter presents the largely unknown insights of the German-Jewish philosopher Franz Rosenzweig and the theologian Joseph Ratzinger/Pope Benedict XVI on Islam. They provide an important perspective – beyond submission.