Ramon Llull (1232-1316), born on Majorca, was one of the most remarkable lay intellectuals of the thirteenth century. He devoted much of his life to promoting missions among unbelievers, the reform of Western Christian society, and personal spiritual perfection. He wrote over 200 philosophical and theological works in Catalan, Latin, and Arabic. Many of these expound on his "Great Universal Art of Finding Truth," an idiosyncratic dialectical system...