Iranian libraries hold only few manuscripts that testify to the extended and intensive Muʿtazilite past in the various centers of Zaydi scholarship in the Caspian region, in Ḫurāsān, and in Rayy. Among the few Muʿtazilite Zaydi works preserved in the libraries of Iran is a miscellany held by the library of the Faculty of Medicine at the University of Shiraz (ʿAllāma Ṭabāṭabāʾī Library). The maǧmūʿa, a facsimile of which is included in the present publication, was written between 673/1274-75 and 676/1277 and contains doctrinal works by Imāmi and Zaydi theologians from both Iran and from Yemen. Most of the codex consists of a theological summa, a taʿlīq that had been composed or transcribed by one Abū Ṭāhir b. ʿAlī al-Ṣaffār which was based on the Kitāb al-Uṣūl by Abū ʿAlī Muḥammad b. Ḫallād al-Baṣrī, the distinguished disciple of the Muʿtazilite theologian and founder of the Bahšamiyya, Abū Hāšim al-Ǧubbāʾī (d. 321/933), with an unknown number of commentary layers in between.