One of Imam Razi's outstanding achievements was his unique interpretive work on the Quran called Mafātiḥ al-Ghayb (Keys to the Unseen) and later nicknamed Tafsīr al-Kabīr (The Great Commentary), one reason being that it was 32 volumes in length. This work contains much of philosophical interest. One of his "major concerns was the self-sufficiency of the intellect." His "acknowledgment of the primacy of the Qur'an grew with his years." Al-Razi's rationalism undoubtedly "holds an important place in the debate in the Islamic tradition on the harmonization of reason and revelation."