The Book of Isaiah (Hebrew: ספר ישעיהו, [ˈsɛ.fɛr jə.ʃaʕ.ˈjaː.hu]) is the first of the Latter Prophets in the Hebrew Bible and the first of the Major Prophets in the Christian Old Testament.[1] It is identified by a superscription as the words of the 8th-century BCE prophet Isaiah ben Amoz, but there is extensive evidence that much of it was composed during the Babylonian captivity and later.[2] Johann Christoph Döderlein suggested in 1775 that the book contained the works of two prophets separated by more than a century,[3] and Bernhard Duhm originated the view, held as a consensus through most of the 20th century, that the book comprises three separate collections of oracles:[4][5] Proto-Isaiah (chapters 139), containing the words of the 8th-century BCE prophet Isaiah; Deutero-Isaiah (chapters 4055), the work of an anonymous 6th-century BCE author writing during the Exile; and Trito-Isaiah (chapters 5666), composed after the return from Exile.[6] Isaiah 1–33 promises judgment and restoration for Judah, Jerusalem and the nations, and chapters 34–66 presume that judgment has been pronounced and restoration follows soon.[7] While virtually no scholars today attribute the entire book, or even most of it, to one person,[4] the book's essential unity has become a focus in more recent research.[8]

The book can be read as an extended meditation on the destiny of Jerusalem into and after the Exile.[9] The Deutero-Isaian part of the book describes how God will make Jerusalem the centre of his worldwide rule through a royal saviour (a messiah) who will destroy the oppressor (Babylon); this messiah is the Persian king Cyrus the Great, who is merely the agent who brings about Yahweh's kingship.[10] Isaiah speaks out against corrupt leaders and for the disadvantaged, and roots righteousness in God's holiness rather than in Israel's covenant.[11]

Isaiah was one of the most popular works among Jews in the Second Temple period (c. 515 BCE – 70 CE).[12] In Christian circles, it was held in such high regard as to be called "the Fifth Gospel",[13] and its influence extends beyond Christianity to English literature and to Western culture in general, from the libretto of Handel's Messiah to a host of such everyday phrases as "swords into ploughshares" and "voice in the wilderness".[14]