One of the most learned men of his day and called the philosopher by contemporaries, George Amiroutzes (c. 1400-c. 1469) attended the Council of Florence (1438-39) as a lay scholar in the Greek delegation. As a high government official in his native Trebizond, he helped to negotiate the surrender of this last independent Greek state to Mehmed the Conqueror in 1461. He eventually entered the Sultan's household as someone with whom Mehmed enjoyed having intellectual discussions. Despite his contemporary fame, however, almost no philosophical writings of his survive. The present work offers an edition of fifteen previously unknown philosophical tractates. Although they are unpublished drafts in a fragmentary state, the tractaes reveal Amiroutzes to be an Aristotelian philosopher influenced by Thomas Aquinas and firmly intent upon refuting Platonism. He also shows himself to be an original thinker in discussing ethics and metaphysics.