The Kitáb-i-Íqán (Persian: كتاب ايقان, Arabic: كتاب الإيقان "The Book of Certitude") is one of many books held sacred by followers of the Bahá'í Faith; it is their primary theological work. One Bahá'í scholar states that it can be regarded as the "most influential Quran commentary in Persian outside the Muslim world," because of its international audience. It is sometimes referred to as the Book of Iqan or simply The Iqan.
The work was composed partly in Persian and partly in Arabic by Bahá'u'lláh, the founder of the Bahá'í Faith, in 1861, when he was living as an exile in Baghdad, then in a province of the Ottoman Empire. While Bahá'u'lláh had claimed to have received revelation some ten years earlier in the Síyáh-Chál (lit. black-pit), a dungeon in Tehran, he had not yet openly declared his mission. References to his own station therefore appear only in veiled form. Christopher Buck, author of a major study of the Íqán, has referred to this theme of the book as its "messianic secret," paralleling the same theme in the Gospel of Mark.
The Íqán constitutes the major theological work of Bahá'u'lláh, and hence of the Bahá'í Faith. It is sometimes referred to as the completion of the Persian Bayán. When it was lithographed in Bombay in 1882, it was the first work of Bahá'í scripture to be published. It was first translated into English in 1904, one of the first works of Bahá'u'lláh to appear in English.Shoghi Effendi, who retranslated the work into English in 1931, referred to the work as follows:
The uncle of the Báb, Ḥájí Mírzá Siyyid Muḥammad, had been perplexed to hear that the promised one of Islam was his own nephew. When he was told that this was the same objection voiced by the uncle of the prophet of Islam, he was shaken and decided to investigate the matter. In 1861 he traveled to Karbila, Iraq, to visit his brother, Ḥájí Mírzá Ḥasan-'Alí, and then went to Baghdad to meet Bahá'u'lláh. There he posed four questions about the signs of the appearance of the promised one in writing to Bahá'u'lláh. The 200 pages (in original languages) of the Kitáb-i-Íqán were written in the course of at most two days and two nights in reply about January 15, 1861.