Józef Mackiewicz (1902–1985) lived from 1955 until his death in Germany. There is, however, very limited research on this period of his life. Almost completely unknown in Poland is the history of German editions of his works. Against this backdrop, the author of this article attempts to discuss this issue comprehensively, based on the writer’s work present in the Polish Museum in Rapperswil. With this, the research desideratum of Mackiewicz’s philology becomes realized, and those interested in the subject gain a valuable insight into previously unknown facts and testimonies of the writer’s life and work in the period in question.