Reading Rosenzweig’s correspondence with different partners allows to enter the laboratory of his work and to follow the steps of his intellectual and spiritual evolution. For instance, his letters accompany the writing of the Star of Redemption and the translation of the Bible with Martin Buber. It also delivers an insight in his understanding of concepts such as dialogue, religion and love. In the following essay I will present a survey of Rosenzweig’s correspondence in its entirety. The aim is to show the editorial situation of Rosenzweig’s private writings. The concrete characteristics of Rosenzweig’s epistolary practice will be examined on the basis of a few examples from the Gritli-letters, showing how the letters contribute to a return to his own Judaism and lay the foundations for an impossible Jewish-Christian dialogue. Finally, I will show the interconnection between Rosenzweig’s correspondence and his thought.