Shaikh Sadooq (ar) narrates :
One night, when I drifted into sleep after thinking about my family, friends and the bounties that the Almighty Allah had bestowed on me, I dreamt that I was performing the circumambulation of the Holy Kaaba in Mecca and in the seventh round I was near the Black Stone (Hajar Aswad), and upon reaching it I was kissing it.
I was saying that I had repaid my trust and fulfilled my covenant so that it might be a witness of this. At that moment I had the honor of seeing my master, the Master of the Age (a.s.) standing at the door of the Kaaba. My heart began to beat fast with excitement and he came to know my inner feelings which were reflected in the worried expression on my face. I saluted him and he replied to my salutation and then asked me: Why don’t you write a book regarding the occultation, so that your sadness and worries are removed?
I said: O son of Allah’s Messenger, I have compiled a number of books about occultation. He said: Not in this style. I order you to compile a book on occultation and therein mention about the occultation of the prophets (peace be on them).
After that, the Imam (a.s.) departed from there. When I woke up, I began to weep, supplicate and express my humility till dawn break. In the morning, in compliance with the commands of the Proof of Allah, I began the compilation of this book. While I pray for the help of Allah and I rely on Him and seek forgiveness for my shortcomings. My Taufeeq is only from the Almighty Allah, I rely on Him and I turn to Him.