Abul Hasan Ali Hajveri (c.990-1077), popularly known as Data Ganj Bakhsh, was born in Ghazna and died in Lahore (now in Pakistan), where he had been living since sometime after 1030. In Secrets and Mysteries (1915-1922) by Iqbal, he appears as a guiding force of Muslim civilization and a role model.
Hajveri wrote many books but his only surviving text is Kashful Mahjub (Revelation of the Mystery), which is nothing less than a miracle of non-fiction art: one of the earliest treatises on Sufism, it remains a standard reference work equally suited to the novice as well as the most advanced scholars even more than nine centuries later.
The book consists of twenty-five chapters. The first fourteen deal with general concepts of Sufism, such as the affirmation of knowledge, poverty, the etymology of Sufism, and so on. Hajveri’s approach in these chapters is distinguished from Qushayri, the author of a multi-volume treatise on mysticism and some other predecessors, since he seems to be more concerned more with giving insight than information.
The last eleven chapters offer a revelation each, from which the book derives its title. These eleven “revelations” are: maarifat (knowledge of the mysteries) of God; unification; faith; purification from foulness; prayer; alms; fasting; pilgrimage; companionship, rules and principles; definitions; and sama (devotional music). It is obvious from the list that Hajveri has based his “revelations” essentially on the obligatory forms of worship and other tenets of Islam practiced by the majority of believers in their everyday lives.