Traditionally the entire book of Isaiah has been viewed as the work of one man who lived from about 760 to 700 b.c. However, for the past two hundred years many interpreters have suggested that this view should be more finely nuanced. The book seems to fall into three major divisions: (1) chs. 1-39, (2) chs. 40-55, (3) chs. 56-66. Chs. 1-39 portray Isaiah as bringing the word of God to bear on Judah (chs. 1-12) and then on the nations around Judah (chs. 13-27), returning to address Judah once again (chs. 28-35), with chs. 36-39 being a historical section repeated from 2Kings 18:17ff. It is clear, however, that chs. 40-55 mark a major change. The location is no longer Jerusalem but Babylon. The time period is following the destruction of Jerusalem in 587 B.C., some 150 years after the death of Isaiah. The prophet calls the people to take heart; God is about to deliver them and take them home. Chs. 56-66 appear to be later still, during the time of restoration when the exiles have returned home and are trying to rebuild their city.
Readers who believe in the limitless power of God will affirm that God could project Isaiah 150 years into the future to produce the material of chs. 40-66. That is not to be doubted. But did God do that? We do not know. When one reads the material carefully, one has the feeling that the author was there among his people, that he sensed their fears and their doubts about God and about Cyrus, and that he was enraged at their propensity toward idolatry. Is it not possible that a subsequent author could have built on the theology of Isaiah, particularly the ideas of God's sovereignty and holiness, the idea of the remnant and the Messiah, and brought them to bear on a later situation. We must remember that the prophetic word was expansive, that is, spoken to a particular situation but having a life of its own, making it applicable to situations in the future.