Originally written as a manual of spiritual instruction, this crucial work of medieval Islamic thought examines Sufi and mystical influences within the Muslim tradition to provide insight into the intellectual and religious history of the Muslim world. Written by one of the most famous theologian-mystics of all time, it is an in-depth discussion of two essential virtues of the religious and spiritual life: patience and thankfulness. In this new edition, the Islamic Texts Society has included a translation of Imam Ghazali's own Introduction to the Revival of the Religious Sciences.