According to some Muslim theologians, God is not free to act; He is bound by human ethics. To be just, He must create an individual of perfect intellect and infallible morality. People are obligated to submit to this person; otherwise eternal damnation awaits them. While these claims may be interpreted as an affront to God’s power, an insult to human judgment and a justification for despotism, Shiʿi Muslims in the eleventh century eagerly adopted them in their attempts to forge a ‘rational’ religious discourse. They utilized everything from literary studies and political theory to natural philosophy and metaphysical speculation in support of this project. This book presents the contribution of al-Sharīf al-Murtaḍān (d. 1044), the thinker most responsible for this irreversible change, which remains central to Imami Shiʿi sectarian identity and conception of history. His debates with Qāḍī ʿAbd al-Jabbār (d. 1024), al-Shaykh al-Mufīd (d. 1022) and al-Shaykh al-Ṭūsī (d. 1067) are the best expression of his intellectual project. The book analyses this project and establishes the dynamic context which prompted him to pour the old wine of Shiʿi doctrine into the new wineskin of systematic Muʿtazili theology.