Abu Jafar, Muhammad b. Yaqub b. Ishāq al-Kulayni Al-Rāzī was among the greatest Shi'a hadithscholars and the author of al-Kafi, the most authentic Shi'a hadith collection and one theFour Books. He was born after the martyrdom of Imam al-'Askari (a), at the time of Imam al-Mahdi (a) and met some hadith transmitters who directly had heard hadiths from Imam al-Hadi (a) and Imam al-'Askari (a). It is said that al-Kulayni was very accurate in transmitting hadiths. Ibn Qulawayh, Muhammad b. Ali Majilawayh al-Qummi, Ahmad b. Muhammad al-Zurari were among his students.
In addition to al-Kafi, al-Kulayni had some other works which show his scientific position in fields other than hadiths; such as,
-Kitab al-Rijal;
-Al-Radd ala l-Qaramita;
-Rasa il al-Aimma
-Al-Ziyy wa l-tajammul;
-Al-Dawajin wa l-rawajin;
-Al-wasail;
-Fadl al-Quran
Up to 50 sources and teachers of al-Kulayni have been mentioned who educated and taught him as well as narrating hadiths for him. His most influential teacher was Ali ben Ibrahim al-Qummi, author of Tafsir Qummiwho has been mentioned in the chain of tramitters of more than 7068 hadiths in al-Kafi. His other famous teachers are:

-Muhammad ben Yahya al-Ash'ari
-Ahmad ben Idris al-Qummi
-Ahmad ben 'Abd Allah ben Ahmad ben Muhammad ben Khalid al-Barqi
-Ahmad ben Muhammad ben 'Isa al-Ash'ari'Abd Allah ben ja'far al-Himyari
-Hasan ben Fadl ben Yazid al-Yamani
-Ahmad ben Mahran
-Muhammad ben Hasan al-Ta'i'
-Ali ben al-Husayn ben Musa ben Babawayh al-Qummi
-Muhammad ben al-Hasan al-Saffar
-Muhammad ben Yahya al-'Attar
-Qasim ben 'Ala
-Ibn 'Uqda