Abu BakrShibli (247-334 AH), the eminent and famous mystical Sufi of Bagdad, despite his great status in mysticism and mystical wayfaring is known for his insanity, which made him known as one of the madmen of the prominent centuries of Islamic mysticism. No doubt those who tried to emphasize his greatness could see through the veil of his abnormal and subversive insanity his hidden wisdom and mystical perception. A glance at the personality and character of this Sufi Master and an analysis of the causes of his madness will help us to understand his real but different character. The present article is an attempt to demonstrate howShibliuses insanity as a mask in order to attain true knowledge.