This is among most well known books regarding Imam Mahdi (a.s.) as it was written for the general populace and not only for the scholarly people. That is why it was written in Persian, which at that time was the language of the majority of Muslims.

The first chapter deals with a brief account of the birth and some circumstances of Imam (a.s.) during the lifetime of his father (a.s.).
Chapter Two is regarding the names and titles of Imam (a.s.).
Chapter Three is about some distinctive qualities of the Imam of the Time (a.s.).
Chapter Four studies the difference among Muslim sects regarding him.
Chapter Five presents evidences that Huijat Ibne Hasan Askari (a.s) is the Promised, Mahdi.
Chapter Six provides proofs of Imamate of the Twelfth Imam through his miracles.
Chapter Seven comprises of incidents of those who met the Imam during Major Occultation.
Chapter Eight reconciles these incidents with claims of meeting the imam during Major Occultation.
Incidents of persons lost in the wild etc. and saved by a holy personality, regarding whom it is not confirmed that he was Imam Asr (a.s.) are mentioned in Chapter Nine.
Chapter Ten is a compendium of duties of the believers towards the Imam of the Age.
Chapter Eleven explains in brief, the times and occasions specially associated with Imam Asr (a.s.).
Chapter Twelve suggests some rituals for getting the honor of seeing Imam Zamana (a.s.).