Although the Commonitorium is among the most famous and influential of fifth-century Latin Patristic works, relatively little is known about its author, Vincent ("the pilgrim," as he calls himself), a late-vocation monk of Lérins Abbey on the Isle of Saint Honorat off the coast of France. Yet the voice that speaks to us from these pages is rich in personality, deftly trained in logic, rhetoric, theology, and history. His thesis is clear, his argument compelling: the Christian faith is rooted in a changeless deposit of faith revealed by God, entrusted to the Apostles and their successors, and, accordingly, incompatible with novelty; progress consists only of a deeper understanding and expression of what remains in itself the same, so that no future formulation can ever contradict what has already been understood and expressed.

Across the centuries, Vincent's Canon-"In the Catholic Church, every care should be taken to hold fast to what has been believed everywhere, always, and by all"-has resounded as a battle cry for defenders of dogmatic tradition; indeed, it served as inspiration and catalyst for John Henry Newman's Essay on the Development of Christian [...] Vincent has also been pressed into service by the Eastern Orthodox, who maintain that his vision is precisely their own; and within the Catholic Church itself, both Pope Francis and his severest critics have cited the Commonitorium in support of their opposing views. Finally, liberal critics reject the validity of Vincent's Canon, asserting there is almost nothing that meets this criterion.

Os Justi Press's edition of the Commonitorium provides the reader with excellent tools for grasping the subtleties of Vincent's argument and for adjudicating the aforementioned interpretations. The original Latin text is given alongside the English translation. Peter Kwasniewski's preface furnishes context, Alan Fimister's theological introduction analyzes the ecclesial and magisterial structure of the Canon, and Phillip Campbell's epilogue defends the concept of the "unanimous consent of the fathers."