This book presents the first edition and translation of Giles of Rome’s Prohemium to his lectures on the Sentences of Peter Lombard (Paris, 1276-1277), together with an extensive introduction. Giles was a student of Thomas Aquinas, yet forged his own path, thereby establishing a distinct late medieval theological tradition, the Augustinian tradition, which should be recognized as such together with the Dominican and Franciscan traditions. Giles defined Theology as “affective knowledge,” a distinct late medieval theological tradition, demarcated from the Dominican view of Theology as speculative, or theoretical knowledge, and the Franciscan view of Theology as practical knowledge.