Rahat al-aql (Peace of Mind), a book to help readers obtain the eternal life of the mind, the paradise of reason, in a constantly changing world, was written by Fatimid theologian Hamid al-Din al-Kirmani.
Hamid al-Din al-Kirmani (d.1020), a prominent Ismaili da’i or missionary, was one of the most learned Ismaili theologians and philosophers of the Fatimid period. Al-Kirmani rose to prominence during the reign of Fatimid Caliph-Imam al-Hakim (r.996-1021).
Hamid al-Din al-Kirmani’s date of birth remains unknown, but he was of Persian origin and was probably born in the province of Kirman. He seems to have spent the greater part of his life as a Fatimid da’i in Iraq, having been particularly active in Baghdad and Basra.
The central headquarters of the Fatimid da’wa in Cairo considered him as the most learned Ismaili theologian of the time. It was in that capacity that al-Kirmani played an important role in refuting the extremist ideas of some of the da’is. Al-Kirmani was summoned in 1014 or shortly earlier to Cairo where he produced several works to disclaim the extremist doctrines. Al-Kirmani’s writings, which were widely circulated, were to some extent successful in checking the spread of the extremist doctrines.
Of his corpus of nearly thirty works, only eighteen seem to have survived. One of his important works, also his final work, is the Rahat al-aql (Peace of Mind). In this work, Al-Kirmani intended to provide the reader an opportunity to understand how to obtain the eternal life of the mind, the paradise of reason, in a constantly changing world.
Manuscripts of Al-Kirmani’s last works can be viewed at the website of The Institute of Ismaili Studies.
Internet Encyclopedia of Philosophy
Hamid Al-Din Al-Kirmani: Ismaili Muslim Thought in the Age of Al-Hakim
Hamid al-Din al-Kirmani by Dr Farhad Daftary
Sayyidna Hamid ad-Din Kirmani By Dr. S. 1. Assaad, Beirut (Lebanon)