Among the primary sources of this study are the books of al-Rijal, which deal with the scientific biographies of the narrators and compilers of traditions by estimating the degree of their authority and deducing their reliability from their dogmatic and political inclinations.
1. The first is Ma'rifat al-Naqilin ‘an al-A'imma al-Sadiqin, compiled by Muhammad b. ‘Umar al-Kashshi. He was a native of the town of Kashsh near Samarqand, where he was brought up under the auspices of the Imamite scholar Muhammad b. Mas'ud al Samarqandi and where he spent the whole of his life. According to al Tusi he died in 368/978.21
Al-Kashshi quoted his information from fifty-three narrators, but his main source was ‘Ali b. Muhammad b. Qutayba of Nishapur22, who was contemporary with the short occultation and had close ties with the agents of the Twelfth Imam in Khurasan. Ibn Qutayba provides important information concerning the evolution of the underground organization of the Imamites (al-Wikala) after al-Sadiq (d. 148/765) and the reason behind the rise of the Waqifite groups after the death of the seventh Imam in 183/799.
Al-Kashshi's work became an important source for later Imamite scholars like al-Tusi (d. 460/1067), who summarised it and gave it the title IkhtiyarMa’rifat al-Rijal.
2,3. Al-Tusi's works, al-Fihrist and al-Rijal, are two of the four main Imamite books of al-Rijal. He cites different chains of transmitters (isnad) regarded as authentic and enables us to discover the links between the Imamite scholars and the agents during the short occultation.
4. The fourth Imamite work on al-Rijal is Fihrist Asma' Musannifi al-Shi’a, which was written by Ahmad b. 'Ali al-Najashi (d. 450/1058), a native of Kufa. He received his Shi’ite education there and then moved to Baghdad, where he was one of the leading Imamite scholars along with al-Murtada (d. 436/1044).
His residing in these two cities enabled him to establish close contact with fortyfive Imamite scholars who had in their possession documents related to the period of the short occultation. These documents cast light on the different ranks within the Imamite organization and provide useful information on works on the Ghayba compiled before and after 260/874.
Al-Barqi (d. 278/891), in his work on al-Rijal, provides valuable reports concerning the relationship between the Imams and their followers in particular the tenth and eleventh Imams, since he was their contemporary.
Despite the fact that the work of al-Dhahabi (d. 748/ 1347) entitled Mizan al-I’tidal is a later source, it contains some reports which elucidate the background of the Ghayba and its connection with the rise of al-Qa’im.