The recent development of documentary literature provides fertile ground for reflection on the literary expression of faith, unbelief, and all the nuances in between that characterize individuals' relationship to religion. In this paper, I will focus on two literary authors, Emmanuel Carrère (born 1957) and Javier Cercas (born 1962) the first of whom describes himself as agnostic and the second as an atheist, who, in first-person documentary narratives, question not only their own relationship to faith, but also that of their loved ones and contemporaries. In Le Royaume (2014), Carrère, drawing on his formative experience of participating in the translation of the Bayard Bible (2001) known as the "Writers' Bible," intertwines a speculative account of the apostle Luke's career as a writer with introspection on his own relationship to the Bible and to faith. In El loco de Dios en el fin del mundo (2025) (written at the request of the Vatican which deliberately approached a non-believing writer), Cercas recounts how he accompanied Pope Francis on one of his last trips and how he questioned the Pope about his faith in the resurrection of the flesh, a question that accompanies all his encounters with various people (his mother, Catholic journalists, clergy, etc.) which the writer recounts. A brief exploration of these two works will allow me to show how non-fiction literary writing is particularly well suited to offering a reflection, or even a conceptualization, of faith and of the relationship to the dogmas of the Catholic Church, which goes beyond a binary position that massively opposes faith and atheism, belief and non-belief, which leads to distinguishing several modes of belief, and also the evolution of belief throughout life.