Thomas Aquinas 
On Faith [PDF ebook] 
Summa Theologiae 2-2, qq. 1–16 of St. Thomas Aquinas

The organization of Thomas Aquinas‘ Summa Theologiae is a remarkable feat of clarity in comparison with its predecessors. Although Aquinas incorporates materials from very different theological traditions he reduces all of these topics to a concise and clear plan. Mark D. Jordan’s translation, On Faith, captures this clarity, Aquinas‘ most characteristic achievement. v. 1. On faith, Summa theologiae, part 2-2, questions 1-16 of St. Thomas Aquinas.