Written around 1873 by Bahá'u'lláh, the founder of the Bahá'í Faith from Iran, this work is written in Arabic and its Arabic title is al-Kitab al-Aqdas, but it is commonly referred to by its Persian title, Kitáb-i-Aqdas, which was given the work by Bahá'u'lláh himself. It is sometimes called "the Aqdas", "the Most Holy Book", "the Book of Laws". and occasionally "the Book of Aqdas".
The Kitáb-i-Aqdas is also referred to as "the Mother-Book" of the Bahá'í Revelation. It is not, however, only a ‘book of laws’, much of the content deals with other matters notably ethical exhortations and addresses to various individuals, groups, and places. The Aqdas also discusses the establishment of Bahá'í administrative institutions, Bahá'í religious practices, laws of personal status, criminal law, ethical exhortations, social principles, miscellaneous laws and abrogations, and prophecies.
The Aqdas is also supplemented by the Questions and Answers, which consists of 107 questions submitted to Bahá'u'lláh by Zaynu'l-Muqarrabin concerning the application of the laws of the Aqdas and Bahá'u'lláh's replies to those questions. Some Texts Revealed by Bahá'u'lláh, a Synopsis and Codification of the Laws and Ordinances of the book, as well as extensive explanatory notes are included as supplementary material in the Kitáb-i-Aqdas.
Some laws and teachings of the Kitáb-i-Aqdas do not yet apply at the present time, and their application depend on decision by the Universal House of Justice.