Al-Shaykh al-Saduq is the title given to Abu Ja’far Muhammad ibn ‘Ali ibn Babawaih al-Qummi (علي بن بابويه القمي), or commonly known in English as Ibn Babawayh. He was the leading traditionist of his time (4th Century A.H.) and one of the most outstanding traditionists of Shi’ite Islam. He earned the title of al-Shaykh al-Saduq on account of his great learning and his reputation for truthfulness. It is a title which he also shares with his father.
Click here for more information.