'Book of Occultation') is a book by the 10th-century Shia scholar Muhammad ibn Ibrahim al-Nu'mani on the subject of the occultation of the last Twelver Imam Muhammad al-Mahdi in 873–4 (260 AH).
The aim of the book was to refute the existing doubts about the occultation and to support it by reason and narration.
Muhammad ibn Ibrahim al-Nu'mani was reportedly a pupil of al-Kulayni (c. 864–941).
[1] Much doubt and skepticism existed in al-Nu'mani' time about the occultation (ghayba) of the last Twelver Imam Muhammad al-Mahdi in 873–4 (260 AH).
He also tried to show that the doubt and ignorance of people originated from the concerns of worldly and mortal aims.