Abû Mansur al-Mâtùrîdî, the founder of the Mâturîdism which has been followed by the majority of the Turks as a theological doctrine, wrote many books on theology, jurisprudence, the foundations of jurisprudence and denominations. However a lot of them could not have been preserved and for many reasons have been lost. Following Abû Hanife, Abû Mansûr al-Mâtùrîdî specialized in religious creed (usûlu’d-Dîn) and jurisprudence (furû‘u’d-dîn). He discussed some important matters previously not discussed by muslim theologians and laid rational, traditional and semantic foundations which have never been used before. One of the most important contributions to the theology made by him was his Epistemology, He tried to apply this epistemology not only to the theology, but also to the science of commentary and jurisprudence. Hence he may well be regarded as one of the early representatives of rational tradition of commentary. He severely criticized the Sufism. Differently from others, he also discriminated the religion (diyanat) from the politics. He made a distinction between belief and deed. His another distinguishing aspect was his discrimination between the Religion and the Sharia. In addition, he sepérated the report of messanger (habar al-rasûl) from the report from messanger (habar min al-rasûl). He was the first who dealt with essential matters which may be currently regarded as the fundamental subjects of Sociology of Knowledge, Philosophy and Philosophy of Religion. In XV. century al-Mâturîdî was found out by the Ottomans once again