Preaching is more than just speaking in public. The persuasion of people and the theory underlying it are precedents of modern propaganda. In his Rhetorica Ecclesiastica, Agostino Valier (1531-1606) outlines what a Catholic preacher should know before he is allowed to deliver his sermons. Closely related to Cardinal Charles Borromeo's entourage and to the directions emanating from the Council of Trent, this treatise was considered to be one of the most influential ones back in the sixteenth and seventeenth centuries and soon became a must for seminaries all over the world. After introducing Valier and the editorial approach he used, Manuel López-Muñoz offers a critical edition of the text aiming to recover the treatise and make it available to modern scholars.