Gregory the Great: Ascetic, Pastor, and First Man of Rome (University of Notre Dame Press, 2015).
The Invention of Peter: Apostolic Discourse and Papal Authority in Late Antiquity (University of Pennsylvania Press, 2013).
Orthodox Constructions of the West, ed. by Demacopoulos and Papanikolaou (Fordham University Press, 2013).
Orthodox Readings of Augustine, ed. by Demacopoulos and Papanikolaou (St. Vladimir’s Seminary Press, 2008).
Five Models of Spiritual Direction in the Early Church (University of Notre Dame Press, 2007).