The Mu'tazila Tafsir, which can be addressed in the general course of rational-Kalam Tafsir, is a significant field resulting from ​​the Quranic efforts of Muslim scholars. Despite its outstanding role in some Sunni’s Kalam Tafsir trends and the modifications of their Tafsir methods and ideas, Mu'tazila Tafsir has been subject to serious critiques due to serious failures in its intellectual foundations and sources of religious knowledge. The present book first addresses the general and theoretical aspects of the subject and studies the Mu'tazila cognitive trends and their positive al-Kalam and cultural influence on the Islamic world. The critical analysis of this Tafsir process is based on a justifiable criterion from religious rationality in the field of religious thought and Quranic Tafsir which supports the rational ijtihadi Tafsir; hence, it is discussed in three areas (foundation, method, and ultimate goal).