This first volume of the smaller works of Thomas Aquinas includes the famous Compendium of Theology: the theological work Aquinas wrote at the request of his secretary, Reginald. It is basically a simplified version of the Summa Theologiae, since his secretary had requested a work on theology in less dense terms. This volume also contains the treatises On the Principles of Nature, On Being and Essence, On Separate Substances, and On Kingship.

Notes on text: 

The Latin text used in this edition is based on the Leonine edition. The English translation of the Compendium of Theology is based on the public domain translation of Cyril Vollert, S.J. The English translation of On the Principles of Nature is based on the public domain translation of Roman A. Kocourek. The English translation of On Being and Essence was prepared by Robert T. Miller. The English translation of On Angels, or On Separate Substances is based on the public domain translation of Francis J. Lescoe. The English translation of On Kingship is based on the public domain translation of Gerald B. Phelan.