Abu Ja’far Muhammad ibn Ya’qub ibn Ishaq al-Kulayni al-Razi (Persian: شیخ ابوجعفر محمّد بن یعقوب بن اسحاق رازی; c. 250 AH/864 CE – 329 AH/941 CE). was a Persian Shiahadith collector.
Al-Kulayni was born in Kulayn, a village or small town situated near Rey, in Iran. His father was Ya’qub al-Kulayni, who is buried at Rey. He belonged to the era of the Minor Occultation of Muhammad al-Mahdi (the last TwelverShia Imam who, according to Shia belief, is currently in occultation and will certainly appear before the Day of Judgment) and is claimed to have greatly benefited from al-Mahdi’s divine knowledge by interacting with him through the Imam’s deputies and emissaries. 
Kulayni received his early religious education in his native town and went to Rey for further education. According to Shia view he is among a special class of muhaddithin known as Rihalah-ye hadith i.e. those who travelled in order to collect ahadith and met the persons considered to be the authority on hadith.
He travelled to Baghdad for this reason and lived there for twenty years, engaged in teaching and pursuing academic work, until he died in 329 AH/941 CE. He is considered the foremost Shia compiler of hadith and was the author of Kitab al-Kafi.
Work and contribution
Although Shaykh al-Kulaynī is most famous for al-Kāfī, this opus was not his only accomplishment. The following is a list of his known works: