This volume provides a brief and accessible introduction to the 9th-century philosopher and theologian John Scottus Eriugena, who was perhaps the most important philosophical thinker to appear in Latin Christendom in the period between Augustine and Anselm. Eriugena was known as the interpreter of Greek thought to the Latin West, particularly as teacher to Frankish emperor Charles the Bald, and this book emphasizes the relation of Eriugena's thought to his Greek and Latin sources, while also looking at his speculative philosophy.