Rev. Guillaume Derville is Full Professor of Theology at the Pontifical University of the Holy Cross in Rome, where he has promoted the center for priestly formation and the institute on the liturgy. His publications include Histoire, mystère, sacrements, L’initiation chrétienne dans l’Òuvre de Jean Daniélou, Devenir fils de Dieu. Une introduction à l’anthropologie théologique, Un seul cœur pour aimer, Eucharistic Concelebration from Symbol to Reality, and Praying 15 Days with St. Josemaria Escriva. Among his pastoral work, he offers spiritual guidance to diocesan priests and Christian formation to lay people in the workplace.