By Sheikh Abu Abdullah Muhammad bin Ibraheem bin Ja'far al-Katib - xkp
It is a helpful paintings, it starts with a few prophetic traditions confirming the imamate of al-Mahdi (s).
Then he mentions the traditions displaying that Allah doesn’t go away the area with out a “Hujjah”. After that he mentions traditions speaking concerning the disappearance of Imam al-Mahdi, his elements, biography, rule and virtues - he mentions the indicators that precede the looks of Imam al-Mahdi (s) along with different topics pertaining to him.
Sheikh al-Mufeed, after pointing out the traditions that ensure the imamate of al-Mahdi, says: “The traditions on which are a number of. the students of Hadith have written them down and categorized them of their books. between these, who've pointed out them with complete information and clarification, is Abu Abdullah Muhammad bin Ibraheem an-Nu’mani in his ebook al-Ghayba…”
The writer has complete the e-book in Thil-Hijja 342AH.