Abstract : By gathering together extracts from his prose writings under the title Des Histoires de passage [Stories of passage], the Swiss-French poet Philippe Jaccottet, born in 1925, highlights the vital importance of the notion of passage in his work. This research proposes to demonstrate that this notion expresses a set of themes, defines a poetic theory and offers an ontological analysis. Reaching beyond the contrast between an attraction to visible passageways in a landscape and an aversion to obstacles [such as a steep mountainside or death, which inspire hope for a " magical " eradication], Jaccottet's sensibility develops a complex interplay between these conflicting concepts and reveals a profound fascination for the point of passage itself : the threshold. Poetic experience gratifies such aspirations, since at certain " privileged " moments it reveals to the poet's " other vision " a world that is open and unified, without barriers or hiatuses. This is achieved here through a particular use of metaphor, itself an active participant in the passage, which allows for a continuous circulation between elements. As a metamorphosis of the world, poetry reveals its connection to the sacred : it " gives onto " " something else " ; it is a pathway, or envisioned pathway, towards a " beyond " which cannot be defined as philosophical, religious, or even, strictly speaking, mystical. Glimpsed in the here and now, the beyond remains inaccessible and indescribable, identified as such through writing, which opens up towards it an infinite vista. The passage is thus within the passage itself, constituting an ontology that leads to a dialectic of limits and the unlimited.