Thomas Aquinas is rivaled in reputation as the paramount Christian intellectual only by Augustine. Venerated within the Catholic church as a saint and as a normative theologian, Aquinas is esteemed in secular circles as a figure of enduring philosophical and cultural significance as well as the archetypal voice of medieval Christianity. Hardly a single modern collection of philosophical arguments for the reality of God, for instance, omits the "five ways" formulated by Aquinas in his Summa Theologiae (Summary of Theology, 1265-1273).

The enormous mass of manuscript works by Aquinas provided, early in the history of printing, for the production of complete, or nearly complete, printed editions of his almost one hundred certainly authentic works, many of them multivolume studies. In modern times this process has reached its apex in the "critical edition" commissioned by Pope Leo XIII and named from this circumstance the Leonine Edition; this work continues...