This book is the first extensive examination of the medieval Qur'an commentary known as the Lata'if al-isharat and the first critical biography of its author, the famous spiritual master Abu al-Qasim al-Qushayri. Written in 5th/11th century Nishapur, an intellectual and cultural crossroads of the Muslim world, the Lata'if al-isharat has endured down through the centuries as an important work of Sufi exegesis. A mystical vision of reality is taught through its line-by-line treatment of the Qur'an as its author was writing as both a Sufi teacher and scholar. This study fully investigates al-Qushayri's life and historical horizon and carefully analyses the structure and method of the commentary. The primary aim of the book is to draw greater attention to the other traditions of exegesis that inform the Sufi approach of the Lata'if al-isharat, an understudied feature of many Sufi commentaries in general. In the case of this commentary, scholarly and pedagogical concerns for language, prophetic sayings, law and theology are interwoven into al-Qushayri's overarching mystical exegesis. Other important aspects of the author's intellectual identity and education clearly influenced the formation of al-Qushayri's Sufi worldview and as a consequence his interpretation of God's word. By delineating these other traditions of exegesis mentioned in al-Qushayri's biography and embedded in his Lata'if al-isharat, we can better appreciate how he and his commentary were part of a wider Sunni historical heritage in addition to the developing Sufi tradition.