by St. Augustine, who wrote a special treatise thereon (De catechizandis rudibus), also, in later times, by Gerson, chancellor of the University of Paris, who wrote "De parvulis ad Christum trahendis"; Clement XI and Benedict XIV gave to it all the weight of their authority, and one of the greatest of all catechists was St. Charles Borromeo. There is the danger, however, from the very nature of the subject, of this form of preaching becoming too dry and purely didactic, a mere catechesis, or doctrinism, to the exclusion of the moral element and of Sacred Scripture. In recent days, organized missionary preaching to non-Catholics has received a new stimulus. In the United States, particularly, this form of religious activity has flourished; and the Paulists, amongst whom the name of Father Hecker is deserving of special mention, are to be mainly identified with the revival. Special facilities are afforded at the central institute of the organization for the training of those who are to impart catechetical instruction, and the non-controversial principles of the association are calculated to commend it to all earnestly seeking after religion. Homiletic Directory In the Roman Catholic Church, the Holy See, through the Congregation for Divine Worship and the Discipline of the Sacraments (headed as of February 2015 by Cardinal Prefect Robert Sarah), has published an official guide and directory for use by bishops, priests, and deacons, who are charged with the ministry of preaching by virtue of their ordination, and for those studying the subject, among others seminarians and those in diaconal formation, called the Homiletic Directory. The Directory was developed in response to a request made by participants in the Synod of Bishops held in 2008 on the Word of God, and in accordance with the instructions of Pope Benedict XVI. Bibliography of historical development St. John Chrysostom and St. Augustine Practice preceded theory. Certain ideas are to be found in the Church Fathers, and these have been collected by Paniel in the introduction to his work "Geschichte der christlich. Beredsamkeit". The first to treat of the theory of preaching was St. John Chrysostom, in his work "On the Priesthood" (peri Hierosynes). Inasmuch as this contains only reflections on preaching, St. Augustine's De doctrina christiana (DDC) might be regarded as the first manual on the subject; its first three books deal with collecting the materials for preaching, "modus inveniendi quæ intelligenda sunt", and the last