The author of the "Epistle on Sufism, Abu 'l-Qasim al-Qushayri" (376/986-465/1074), was a famous Sunni scholar and mystic (Sufi) from Khurasan in Iran. His Epistle is probably the most popular Sufi manual ever. Written in 437/1045, it has served as a primary textbook for many generations of Sufi nov[...]