You have asked me, O brother in the faith, to expound the aim and the mysteries of religious sciences, the boundaries and depths of theological doctrines. You wish to know my experiences while disentangling truth lost in the medley of sects and divergencies of thought, and how I have dared to climb from the low levels of traditional belief to the topmost summit of assurance. You desire to learn what I have borrowed, first of all from scholastic theology; and secondly from the method of the Ta’limites, who, in seeking truth, rest upon the authority of a leader; and why, thirdly, I have been led to reject philosophic systems; and finally, what I have accepted of the doctrine of the Sufis, and the sum total of truth which I have gathered in studying every variety of opinion. You ask me why, after resigning at Bagdad a teaching post which attracted a number of hearers, I have, long afterwards, accepted a similar one at Nishapur. Convinced as I am of the sincerity which prompts your inquiries, I proceed to answer them, invoking the help and protection of God. Know then, my brothers (may God direct you in the right way), that the diversity in beliefs and religions, and the variety of doctrines and sects which divide men, are like a deep ocean strewn with shipwrecks, from which very few escape safe and sound. Each sect, it is true, believes itself in possession of the truth and of salvation, “each party,” as the Koran saith, “rejoices in its own creed”; but as the chief of the apostles, whose word is always truthful, has told us, “My people will be divided into more than seventy sects, of whom only one will be saved.” This prediction, like all others of the Prophet, must be fulfilled. From the period of adolescence, that is to say, previous to reaching my twentieth year to the present time when I have passed my fiftieth, I have ventured into this vast ocean; I have fearlessly sounded its depths, and, like a resolute diver, I have penetrated its darkness and dared its dangers and abysses. I have interrogated the beliefs of each sect and scrutinised the mysteries of each doctrine, in order to disentangle truth from error and orthodoxy from heresy. I have never met one who maintained the hidden meaning of the Koran without investigating the nature of his belief, nor a partisan of its exterior sense without inquiring into the results of his doctrine. There is no philosopher whose system I have not fathomed, nor theologian the intricacies of whose doctrine I have not followed out. Sufism has no secrets into which I have not penetrated; the devout adorer of Deity has revealed to me the aim of his austerities; the atheist has not been able to conceal from me the real reason of his unbelief. The thirst for knowledge was innate in me from an early age; it was like a second nature implanted by God, without any will on my part. No sooner had I emerged from boyhood than I had already broken the fetters of tradition and freed myself from hereditary beliefs.