This study of the Byzantine philosopher George Gemistos Plethon includes the first complete translation of his treatise, On the Differences of Aristotle from Plato, and summarizes all his other works. Woodhouse emphasizes Plethon's controversy with George Scholarios on the respective merits of Plato and Aristotle and his important impact on the Italian humanists during the Council of Union at Ferrara and Florence in 1438-9. Though Plethon's ambition to create a new religion based on Neoplatonism was never realized, his ideas had a significant influence on the western Renaissance.