At the end of his life, François Mauriac evokes a delusive conviction that briefly assailed him when he was about ten years old : his father, deceased when he himself was only twenty months old, would be, in reality, always alive. While leaning on the elements of the author’s life, and particularly his intimacy with the Christian faith, we propose the hypothesis that, for this young boy, puberty was the moment of a psychical trauma, likely to provoke regressive movements, without inducing the establishment of a psychotic structure. Maybe this almost pathological moment would be an attempt to compensate for the father’s lack by means of an hallucinated creation.