 Biographical entries in the "Tabaqat" literature typically offer evaluations of the personal, religious and intellectual quality of their subjects.Famous examples of Tabaqat literature include Tabaqat al-Hanabilah originally by Ibn Abi Ya'la and then by Ibn Rajab.Tabaqat ul-Mutazilah (as the title suggests, concerned with Islamic theologians of the Mutazilite school) by Ahmad bin Yahya al-Murtada, at-Tabaqat ul-Kubra (about the companions of the Prophet and their successors) by Ibn Sa'd and - more recently - Tabaqat 'Alam ul-Shi'ah (about famous Shi'a scholars] by Aqa Buzurg Tehrani.