The Book of Isaiah was probably written by several prophets
The book bears the name of an 8th-century BCE prophet from Judah, yet from chapter 40 onward Isaiah's name vanishes, the style shifts and the text speaks as if the Babylonian exile were already ending. Scholars since 1775 have concluded that other anonymous writers extended it, a practice ancient Israel did not consider improper.
Isaiah heads the Latter Prophets of the Hebrew Bible and opens the major prophets in the Christian Old Testament. Johann Christoph Döderlein suggested in 1775 that it held the work of two prophets more than a century apart. Bernhard Duhm then proposed three collections, a view that dominated the 20th century: First Isaiah in chapters 1 to 39, largely the original prophet's words; Second Isaiah in chapters 40 to 55, written anonymously during the exile and nicknamed the Book of Consolation; and Third Isaiah in chapters 56 to 66, composed after the return.
The evidence is threefold. Chapters 40 to 55 assume Jerusalem already lies in ruins, and later chapters assume the Temple is being rebuilt. The prophet's name disappears after chapter 39, and vocabulary and theology change abruptly. John Barton goes further, accepting only chapters 1 to 8 and 28 to 31 as genuine sayings. From the late 20th century some scholars instead read the book in two literary halves split between chapters 33 and 34, judgment followed by restoration, and stressed its unity, though the three-part model still has wide support.
The historical Isaiah lived under four kings of Judah while the Neo-Assyrian Empire pushed west, destroying the northern Kingdom of Israel in 722–721 and subjugating Judah in 701. The book condemns corrupt rulers and defends the disadvantaged, grounding righteousness in God's holiness. Its later chapters present the Persian king Cyrus the Great as a messiah, the agent through whom Jerusalem will become the centre of God's rule.
Isaiah was among the most popular texts of the Second Temple period, and Christians, reading its suffering servant as Jesus, called it the Fifth Gospel. Its reach extends to Handel's Messiah and to everyday English phrases such as swords into ploughshares and a voice in the wilderness.
Source: Book of Isaiah
