Al-Sulami (d. 412/1021) was an influential classical Sufi master whose works espoused companionship as a way for believers to experience God's guidance and cultivate religious virtues. This book provides a historical reconstruction of Sufi companionship in Khurasan in the period, arguing that al-Sulami's concept of suhba (companionship) envisioned the transformation of society as whole, not just the master-disciple relationship. Bringing debates in contemporary virtue ethics to bear on al-Sulami's spiritual method, the book offers an original analysis of the latter's thought that will be of interest to scholars of early Islam and classical Sufism as well as moral theologians interested in virtue ethics, character and friendship.