The writer says that the first time the term Ghaybat (absence or disappearance) was introduced, it was in the book by the name of Kamaluddin. He says that it is likely that Kulaini too might have explained such a thing earlier.
First fact is regularly being ignored time and again, forgotten by the writer that the sense and the meaning of Ghaybat was already a known fact, as it was in the traditions and the narration that have hailed immediately from the Prophet (S) and the Imams. So, the occurrence of such an event Ghaybat was an event not a surprise.
The awareness of the people towards this fact is older than the book Kamaluddin of Saduq and the book Kafi of Kulaini. They did not invent it but mentioned the traditions about it. If anyone were to give an explanation of the Ghaybat it could have been the same about Saduq and Kafi have told in their books.
Besides, those who have survived both the periods of the Ghaybat (absence or occultation) have told the same thing and have narrated their experience. What was foretold, is narrated; and what was foretold took place.