First paragraph: Scholars of Islamic studies have increasingly come to recognize the importance of the Ibāḍiyya as a group that preserves a unique perspective on Islam: as the only surviving sectarian relatives of the Khārijites, the Ibāḍiyya offer important non-Sunnī and non-Shīʿī views on early Islamic history, theology and law. Contemporary Ibāḍīs of North Africa and Oman possess a remarkable corpus of texts, some of which date back to the early medieval period of Islamic history. Large collections of Ibāḍī manuscripts can also be found in Egypt and Tanzania (specifically in Zanzibar). Many important Ibāḍī works have become available to researchers in recent decades, due in part to the efforts of individual Ibāḍī and non-Ibāḍī scholars, but especially to the Omani Ministry of National Heritage and Culture (Wizārat al-turāth al-qawmī wa-l-thaqāfa). Nevertheless, and despite these welcome strides forward, much Ibāḍī material remains in manuscript form. In the work under review, Drs. Madelung and al-Salimi present in critical Arabic edition three heretofore unpublished early Ibāḍī works by Abū l-Mundhir Bashīr ibn Muḥammad ibn Maḥbūb (d. ca. 290/908): the Kitāb al-raṣf fī l-tawḥīd (Book of Paving about Divine Unity), Kitāb al-muḥāraba (Book of Warfare) and the Sīra (Epistle). In addition, the authors supply a short five page introduction, in English, discussing the author, the texts and manuscripts consulted for the edition, as well as a list of works cited (in Arabic).