This volume offers the first comprehensive introduction in English to the study of the philosopher and theologian Raimundus Lullus (c. 1232-1316).From the 1270s onwards Lullus worked on his Art: a philosophico-theological system which takes the basic concepts of the three monotheistic religions of its time and discusses them by means of rational discourse in order to convince Muslims (and Jews) of the truth of the Christian articles of faith. Revising his Art and extending it across all fields of human knowledge, Lullus created a universal science that strongly influenced thinkers such as Nicholas of Cusa and Leibniz. He produced some 280 works in both Catalan and Latin, the Latin Opera currently being edited in the Corpus Christianorum, Continuatio Mediaevalis series.