The Kitáb-i-Aqdas is a central book of the Bahá'í Faith written by Bahá'u'lláh, the founder of the religion. The work was written in Arabic under the Arabic title al-Kitáb al-Aqdas (Arabic: الكتاب الاقدس), but it is commonly referred to by its Persian title, Kitáb-i-Aqdas (), which was given to the work by Bahá'u'lláh himself. It is sometimes also referred to as "the Aqdas", "the Most Holy Book", "the Book of Laws" and occasionally "the Book of Aqdas".