Thomas Aquinas

Summa Theologica

The Greatest Classics of Theology

On the Unity of the Intellect

On Being and Essence

Nature and Grace: Selections from the Summa Theologica

Selections from the Summa Theologica (Modern Edition)

Summa Theologica : Volume 1, Part 1 (Prima Pars)

Summa Theologica : Volume 2, Part 1 of 2 (Prima Secundae)

Summa Theologica : Volume 4, Part 3 (Tertia Pars)

Summa Theologica : Volume 3, Part 2 of Part 2 (Secunda Secundae)

Summa Theologica : Volume 5, Supplement to Part 3

The Aquinas Catechism: A Simple Explanation of the Catholic Faith by the Church's Greatest Theologian (Unabridged)