Our research suggests al-Shaykh al-Mufīd was the first author to write down “Systematic Kalām” within framework of Imāmiyya works, which has survived present day. He reviewed and rationalized theological issues Imāmiyya, produced major works like Taṣḥīḥ al-I‘tiqādāt, Awā’il al-Maqālāt, al-Nukat fī Muqaddimāt al-Uṣūl, al-I‘tiqādiyya, in that context. While method content seem be influenced by Ba...