At-Tafsir al-Kabir li Fakhr ad-Din ar-Razi (604H) - Mafatih al-Ghayb

It is regarded as the largest Tafsir (interpretation) based on rational discretion and reason, in which the author mentions the causes of the revelation of the surahs and the occasions that took place between them. He proceeds with a detailed interpretation of the universal sciences, and does not forget to mention the fundamental, grammatical and rhetorical issues, as well as the rational deductions.

In his Tafsir, Al-Razi explains the meanings of the Noble Qur’an and its Signs. It contains extensive research in various Islamic sciences, such as theology, and the sayings of philosophers and people of wisdom. Al-Razi mentions the doctrines of jurists and their evidence in the Verses of legislation; he successfully supports the doctrine of Ahlu-Sunnah Wal Jama'ah and refutes that of the Mu'tazilah, the sayings of erring sects, and disproves the opinions of the philosophers.

This book is considered to be one of the greatest, most significant and broadest books of interpretation of the Holy Quran.

However, since Al-Razi did not complete it, Shihab Ad-Din Al-Khubi Ad-Dimashqi (639 AH) took the initiative to complete a portion of it, then came Najm Al-Din Al-Qamuli (727 AH) after him, and finished the last part, in a manner that cannot distinguish the original from the complement.

Beautiful Egyptian edition in 16 volumes, with authentication of the Hadiths.