In A Canticle for Leibowitz, Walter M. Miller, Jr. tells a grim narrative of the future of human civilization. The author’s reliance on the themes of recurrence and religion distinguishes the novel from similar works in the science fiction genre, and are key elements in framing Miller’s post-apocalyptic vision. This essay argues that these themes are employed by the author in order to establish the fall of humanity as part of an inevitable cycle. Central aspects of Judeo-Christian tradition, such as the fall, the burden of original sin and the deluge, are discerned in Miller’s narrative, and linked to the concepts of destruction and restoration in the novel. The loss of an original place of perfection, and humanity’s inability to return to that place, is argued to be central to the cycle’s repetition. The Catholic perception of original sin as hereditary is argued to be pivotal in the failure to achieve that return. The cyclic aspect of the return is also shown to contrast with the linear elements of the novel, particularly in light of the Christian eschatology and the linear progression of time. Furthermore, this essay discerns the different expressions of recurrence in miller’s narrative, ranging from structure and characters to theme. It is demonstrated how the author, through the application of recurrence, affirms the cyclic aspect of the narrative structure. Also, it is argued that its implementation serves to infuse the novel with sentiments of inevitability concerning the progression of the cycle.