This work examines the theological thought of Adudüddin al-Ijî, a leading 14th-century Muhakkiq theologian whom Hafiz Shirazi (d. 756/1355) described as "the sultan of sultans in the realm of knowledge." In this context, the theological thought, the central theme (aslu'l-usûl) of theology, is presented under three main headings from the Ijî perspective. This book offers in-depth analyses of numerous challenging problems in theology, from the divine names and attributes to the relationship between God and the universe.