Abū ʿAlī Muḥammad Ibn Khallād al-Baṣrī was a distinguished disciple of the Muʿtazilī theologian and founder of the Bahshamiyya, Abū Hāshim al-Jubbāʾī (d. 321/933). He is reported to have written a theological summa, Kitāb al-Uṣūl, as well as an autocommentary. None of the works of Ibn Khallād has come down to us directly, although substantial portions of his Kitāb al-Uṣūl and/or Sharḥ al-Uṣūl have reached us embedded in the Kitāb Ziyādāt Sharḥ al-Uṣūl by the Zaydī Imām al-Nāṭiq bi-l-ḥaqq Abū Ṭālib Yaḥyā b. al-Ḥusayn b. Hārūn al-Buṭḥānī (d. 424/1033). The present volume contains an editio princeps of the text of the Ziyādāt, based on what seems to be a unique manuscript, owned by Leiden University Library (Cod. Or 2949 [= Arab 2307]).