This volume does not intend to be a biography of Paul VI whose personality, teaching, and pontificate have been the object of increasing scholarly attention in recent years. The aim here is rather to increase our awareness of the holiness of this pope—whose influence over the course of the Catholic Church in the twentieth century cannot be underestimated—through the cause for his beatification of which the author, as a member of the Congregation for the Causes of Saints, was the Reporting Judge (Relator or Ponens Causae).