The movement of Islamic radicalism, especially in the Middle East region that the majority of the population is Muslim, led to a negative image against Islam that was promoted as a peace-loving and tolerant religion. The bad phenomenon is certainly not reflective of the actual of Islamic teachings, because the essence of Islam is bringing the grace for the whole universe. This paper is the result of the author’s literary research related to epistemology of Muslim radicalism from various schools that have the same point of view in understanding the teachings of Islam. The epistemology model of radical Muslim in understanding the Islamic teachings apparently has a strong influence to the religiosity behavior in social life which culminate in exclusive, radical, and offensive attitude, both to fellow Muslims of different views as well as to non-Muslims. This study aims to reveal the uniqueness of the epistemology of Muslim radicalism community in understanding the Qur’an and Hadith, thus changing the face of essential Islam (rahmatan li al-‘alamin) into a spooky and scary face. The author used hermeneutics approach in analyzing the documentary data which were collected for revealing the historical, sociological or philosophical epistemology background of radical Muslim community. The findings of this research is that the radical Muslim community just hold on Qur’an and Hadith that is understood literally, word to word, and scripturally, thus giving birth to the understanding, fanatical, exclusive, and black-and-white.