Michel de Certeau (1925-1986) was a boundary-crosser throughout his life between scientific disciplines: from theology to historical anthropology to psychoanalysis, he traversed various fields of the sciences of the Other. Figures of alterity can be understood as a unifying thread in de Certeau's studies, which he developed through early modern mysticism as well as through theories of history or the cultural history of the city and consumption. The work of the French Jesuit has thus become a significant reference point today for such diverse approaches as Cultural Studies, postmodern theology, new cultural history, or postcolonial theories. Through his most important writings, central concepts and terms of this innovative thinker in transdisciplinary cultural studies are explained.