Since the publication of the volume poèmes – poëtra (2015), which contains poems from three decades, the œuvre of the German poet Rainer René Mueller (*1949) has gained increasing and enthusiastic attention from both critics and the general public. By looking closely at three central motives (the concept of Lied, the question of provenance, the figure of the stone) the present paper intends to provide for the first time a comprehensive overview of Mueller’s poetical stance. At its center stands the traditionally charged question: What is German? In his work, Mueller insistently poses it, in particular with regard to the breaks and contradictions in the history of both German and Germany. Through the interpretation of chosen passages from representative poems and by taking into account unpublished texts from Mueller’s archive, the paper seeks to show the specificity of Mueller’s writing and style. According to Mueller’s own early programmatic statement, he brought Kassiber into the world – secret messages to those who are willing to lend an attentive ear.