The first five chapters of this work are a Jewish expansion of 2 Kings, detailing the martyrdom of Isaiah. Chapters 6-11 are a Christian work which detail Isaiah’s ascension through the seven heavens. This section is akin to the apocalyptic literature of Enoch in that Isaiah’s soul is ushered through various stages of heaven. Each section is a composite of various sources. This complicates the dating of the book. The Jewish section was likely written in Hebrew and translated into Greek. Hebrews 11 appears to refer to the martyrdom of Isaiah (“some were sawn asunder”) or the same tradition that Isaiah the prophet was martyred by being sawn in half. This would imply a date prior to the late first century.This was the state of the question until the early 1980s. But more recent scholarship on the Ascension of Isaiah (the preferred title now) doubts this division into a Jewish source and a Christian source. Rather, it seems to be a single second-century Christian composition. The work by Mauro Pesce, Enrico Norelli. et al., is in French and Italian, and so has not always received adequate attention in the English-speaking world. The work in English by Robert Hall and Jonathan Knight has also been important. Richard Bauckham has also published on this text and he surveys the major issues in his article "The Ascension of Isaiah: Genre, Unity and Date," which you can read part of here. See also Darrel Hannah's article, Isaiah's vision in the ascension of Isaiah and the early church.
For notice of past posts in Phil Long's ongoing series on the Old Testament Pseudepigrapha, start here and follow the links.
UPDATE: At the Vridar Blog, Neil Godfrey has summarized some of Norelli's work on the Ascension of Isaiah.
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