The Oratorian priest Antonio Gallonio (1556-1605) devoted his life to writing about saints. The thread running through his hagiographical oeuvre was renunciation of this world: humility, subservience and endurance. Yet he engaged with the expertise of lay people, jurists, physicians and engineers, so as to appeal to their interests and convert them. In order to emphasize how saints endured torture, healed disease and exercised piety rather than ingenuity, Gallonio ventured into those secular disciplines, even if he did not endorse them. This book surveys Gallonio’s published and unpublished works and his position in Roman society, to expose the tensions between a theocratic clergy and the self-assertion of skilled and scholarly professionals in the Italian Counter-Reformation.