The edition is a diplomatic edition based on the text of the Arabic version of IV Ezra as found in the unique tenth-century manuscript Ms Mt Sinai Arabic Codex 589 which contains the full text of this version. It is a translation of a Syriac text closely related to the sole survivor in Ms Milan, Ambrosian Library, B. 21 Inf. It is not identical with any of the other known Arabic versions of IV Ezra, which appear to have been translated from the Greek. The introduction to the edition contains a description of the manuscript, a discussion of its orthography and its scribal mistakes and of the adopted method of text edition. The translation is an annotated translation. The introduction deals among others with the relation between the Syriac version of IV Ezra and its Arabic translation, the fragment in Ms Berol. Sprenger 30 (Ahlwardt 9434), the relation between the Arabic version of IV Ezra and the Arabic version of the Apocalypse of Baruch in the same manuscript and the occurence of Middle Arabic elements in the text.