Kimiya-yi Sa'ādat was a book written by Abū Ḥāmid Muḥammad ibn Muḥammad al-Ghazālī, a Persian theologian, philosopher, and prolific Sunni Muslim author regarded as one of the greatest systematic thinkers of Islam. The Kimiya-yi Sa'ādat was written towards the end of his life shortly before 499 AH/1105 AD