The Great Commentary, or Keys to the Unseen, is a book of Quranic exegesis written by Sheikh al-Islam Fakhr al-Din al-Razi (544–606 AH). The Great Commentary and Keys to the Unseen are two sides of the same coin, as they are two well-known names among scholars and researchers for a single commentary written by Imam Fakhr al-Din al-Razi. Some scholars have attempted to combine these two names, arguing that al-Razi wrote his great commentary, called Keys to the Unseen. This commentary is considered the most important and, indeed, the best of all the commentaries of the interpretive school that adheres to the school of interpretation based on the commendable opinion. It is a scientific encyclopedia specializing in the field of Islam in general, and the science of Quranic exegesis in particular. Furthermore, it is the foundation of rational interpretations of the Quran, representing the pinnacle of rational attempts to understand the Quran. It is a vast repository of rational guidance and theoretical insights into Quranic exegesis. It is considered a comprehensive commentary because it combines interpretation based on sound reason and authentic transmission, in addition to its extensive research covering various types of scientific issues. It is considered one of the longest commentaries, ancient and modern, and the most detailed in presenting opinions, discussing different beliefs and doctrines. In it, Imam al-Razi mentions the connection between the surah and others, mentions the connections between the verses, digresses into cosmic sciences and expands on them, as well as mentions the fundamental issues, grammar, rhetoric, and rational deductions. In his commentary, he clarifies the meanings of the Holy Quran and its allusions, and contains extensive research in various Islamic sciences, such as theology and the sayings of the philosophers. He mentions the schools of thought of the jurists and their evidence in the verses of legal rulings, supports the Sunni school of thought in creed, responds to the Mu'tazila and the sayings of the deviant sects, and refutes their doctrines, just as he responds to the philosophers. This book is considered one of the most important and greatest books of commentary, the most comprehensive, and the most abundant in material.
