Each volume of this series of companions to major philosophers contains specially commissioned essays by an international team of scholars, together with a substantial bibliography, and will serve as a reference work for students and non-specialists. One aim of the series is to dispel the intimidation such readers often feel when faced with the work of a difficult and challenging thinker. Plotinus was the greatest philosopher in the 700-year period between Aristotle and Augustine. He thought of himself as a disciple of Plato, but in his efforts to defend Platonism against Aristotelians, Stoics, and others, he actually produced a reinvigorated version of Platonism that later came to be known as 'Neoplatonism'. In this volume, sixteen leading scholars introduce and explain the many facets of Plotinus' complex system. They place Plotinus in the history of ancient philosophy while showing that he was a founder of medieval philosophy.