This is the most thorough investigation yet published on the early Christian apocalypse called the 'Ascension of Isaiah'. Knight examines all the critical issues in the study of this document, including matters of date, provenance and purpose. Particular attention is paid to the book's concepts of christology (with a view both to that christology's Jewish mediatorial background and to its relationship with wider Christianity) and millenarianism (with a view to the social setting of the writer and his readers). Questions concerning the author as haggadist and exegete are also addressed.