The Holy Man whose life we have undertaken to record must be regarded from two points of view: first, as the Providential instrument of propagating the work of reparation for the blasphemy and impiety which are provoking the anger of God against this generation, and, in particular, of establishing the devotion to the Holy Face, which is so intimately connected with that of reparation; secondly, as an example in his own person of the most exalted perfection. Living in and mixing with the world, he was not of the world, and yet this separation was not marked by any outward singularity of behaviour or austere reserve. He is thus placed more naturally within the sphere of imitation.
...it has pleased Providence to raise up and set before us, in these days of cold unbelief and apologetic faith, a pattern layman, in whom the rules of the world in these matters are completely ignored and disregarded, and to set a seal of approval upon his conduct in this respect by a profusion of marvellous cures, performed as it were to order, and of which a parallel can scarcely be found since the time when St. Vincent Ferrer used to ring a bell at the hour when he worked his miracles. Much more, it need scarcely be said, can be learned from Léon Dupont's life, but this lesson lies on the surface, and may well be supposed to have a special purpose and significance—namely, to rebuke the pride and incredulity of the age, and to foster in the hearts of the Church's children the humble and simple faith of primitive times.
(excerpt from the editor's preface)