The Book of Isaiah (Hebrew: , ['s?.f?r j?.?a?.'ja:.hu]) is the first of the Latter Prophets in the Hebrew Bible and the first of the Major Prophets in the Christian Old Testament. 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. Johann Christoph Döderlein suggested in 1775 that the book contained the works of two prophets separated by more than a century, 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: Proto-Isaiah (chapters 1-39), containing the words of the 8th-century prophet Isaiah; Deutero-Isaiah (chapters 40-55), the work of an anonymous 6th-century BCE author writing during the Exile; and Trito-Isaiah (chapters 56-66), composed after the return from Exile. 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. While virtually no scholars today attribute the entire book, or even most of it, to one person, the book's essential unity has become a focus in more recent research.
The book can be read as an extended meditation on the destiny of Jerusalem into and after the Exile. 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 her oppressor (Babylon); this messiah is the Persian king Cyrus the Great, who is merely the agent who brings about Yahweh's kingship. Isaiah speaks out against corrupt leaders and for the disadvantaged, and roots righteousness in God's holiness rather than in Israel's covenant.
Isaiah was one of the most popular works among Jews in the Second Temple period (c. 515 BCE - 70 CE). In Christian circles, it was held in such high regard as to be called "the Fifth Gospel", 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".
General scholarly consensus through most of the 20th century saw three separate collections of oracles in the book of Isaiah. A typical outline based on this understanding of the book sees its underlying structure in terms of the identification of historical figures who might have been their authors:
While one part of the general consensus still holds, this perception of Isaiah as made up of three rather distinct sections underwent a radical challenge in the last quarter of the 20th century. The newer approach looks at the book in terms of its literary and formal characteristics, rather than authors, and sees in it a two-part structure divided between chapters 33 and 34:
Seeing Isaiah as a two-part book (chapters 1-33 and 34-66) with an overarching theme leads to a summary of its contents like the following:
The older understanding of this book as three fairly discrete sections attributable to identifiable authors leads to a more atomised picture of its contents, as in this example:
While it is widely accepted that the book of Isaiah is rooted in a historic prophet called Isaiah, who lived in the Kingdom of Judah during the 8th century BCE, it is also widely accepted that this prophet did not write the entire book of Isaiah.
The composition history of Isaiah reflects a major difference in the way authorship was regarded in ancient Israel and in modern societies; the ancients did not regard it as inappropriate to supplement an existing work while remaining anonymous. While the authors are anonymous, it is plausible that all of them were priests, and the book may thus reflect Priestly concerns, in opposition to the increasingly successful reform movement of the Deuteronomists.
The historic Isaiah ben Amoz lived in the Kingdom of Judah during the reigns of four kings from the mid to late 8th-century BCE. During this period, Assyria was expanding westward from its origins in modern-day northern Iraq towards the Mediterranean, destroying first Aram (modern Syria) in 734-732 BCE, then the Kingdom of Israel in 722-721, and finally subjugating Judah in 701. Proto-Isaiah is divided between verse and prose passages, and a currently popular theory is that the verse passages represent the prophecies of the original 8th-century Isaiah, while the prose sections are "sermons" on his texts composed at the court of Josiah a hundred years later, at the end of the 7th century.
The conquest of Jerusalem by Babylon and the exile of its elite in 586 BCE ushered in the next stage in the formation of the book. Deutero-Isaiah addresses himself to the Jews in exile, offering them the hope of return. This was the period of the meteoric rise of Persia under its king Cyrus the Great - in 559 BCE he succeeded his father as ruler of a small vassal kingdom in modern eastern Iran, by 540 he ruled an empire stretching from the Mediterranean to Central Asia, and in 539 he conquered Babylon. Deutero-Isaiah's predictions of the imminent fall of Babylon and his glorification of Cyrus as the deliverer of Israel date his prophecies to 550-539 BCE, and probably towards the end of this period.
The Persians ended the Jewish exile, and by 515 BCE the exiles, or at least some of them, had returned to Jerusalem and rebuilt the Temple. The return, however, was not without problems: the returnees found themselves in conflict with those who had remained in the country and who now owned the land, and there were further conflicts over the form of government that should be set up. This background forms the context of Trito-Isaiah.
Isaiah is focused on the main role of Jerusalem in God's plan for the world, seeing centuries of history as though they were all the single vision of the 8th-century prophet Isaiah. Proto-Isaiah speaks of Israel's desertion of God and what will follow: Israel will be destroyed by foreign enemies, but after the people, the country and Jerusalem are punished and purified, a holy remnant will live in God's place in Zion, governed by God's chosen king (the messiah), under the presence and protection of God; Deutero-Isaiah has as its subject the liberation of Israel from captivity in Babylon in another Exodus, which the God of Israel will arrange using Cyrus, the Persian conqueror, as his agent; Trito-Isaiah concerns Jerusalem, the Temple, the Sabbath, and Israel's salvation. (More explicitly, it concerns questions current among Jews living in Jerusalem and Palestine in the post-Exilic period about who is a God-loving Jew and who is not). Walter Brueggemann has described this overarching narrative as "a continued meditation upon the destiny of Jerusalem".
God's plan for the world is based on his choice of Jerusalem as the place where he will manifest himself, and of the line of David as his earthly representative - a theme that may possibly have been created through Jerusalem's reprieve from Assyrian attack in 701 BCE.  God is "the holy one of Israel"; justice and righteousness are the qualities that mark the essence of God, and Israel has offended God through unrighteousness. Isaiah speaks out for the poor and the oppressed and against corrupt princes and judges, but unlike the prophets Amos and Micah he roots righteousness not in Israel's covenant with God but in God's holiness.
Isaiah 44:6 contains the first clear statement of monotheism: "I am the first and I am the last; beside me there is no God". In Isaiah 44:09-20, this is developed into a satire on the making and worship of idols, mocking the foolishness of the carpenter who worships the idol that he himself has carved. While Yahweh had shown his superiority to other gods before, in Second Isaiah, he becomes the sole God of the world. This model of monotheism became the defining characteristic of post-Exilic Judaism and became the basis for Christianity and Islam.
A central theme in Second Isaiah is that of a new Exodus - the return of the exiled people Israel from Babylon to Jerusalem. The author imagines a ritualistic return to Zion (Judah) led by Yahweh. The importance of this theme is indicated by its placement at the beginning and end of Second Isaiah (40:3-5, 55:12-13). This new Exodus is repeatedly linked with Israel's Exodus from Egypt to Canaan under divine guidance, but with new elements. These links include the following:
Isaiah was one of the most popular works in the period between the foundation of the Second Temple c. 515 BCE and its destruction by the Romans in 70 CE. Isaiah's "shoot [which] will come up from the stump of Jesse" is alluded to or cited in the Psalms of Solomon and various apocalyptic works including the Similitudes of Enoch, 2 Baruch, 4 Ezra, and the third of the Sibylline oracles, all of which understood it to refer to a/the messiah and the messianic age. Isaiah 6, in which Isaiah describes his vision of God enthroned in the Temple, influenced the visions of God in works such as the "Book of the Watchers" section of the Book of Enoch, the Book of Daniel and others, often combined with the similar vision from the Book of Ezekiel. A very influential portion of Isaiah was the four so-called Songs of the Suffering Servant from Isaiah 42, 49, 50 and 52, in which God calls upon his servant to lead the nations (the servant is horribly abused, sacrifices himself in accepting the punishment due others, and is finally rewarded). Some Second Temple texts, including the Wisdom of Solomon and the Book of Daniel identified the Servant as a group - "the wise" who "will lead many to righteousness" (Daniel 12:3) - but others, notably the Similitudes of Enoch, understood it in messianic terms. The earliest Christians, building on this second tradition, interpreted Isaiah 52:13-53:12, the fourth of the songs, as a prophecy of the death and exaltation of Jesus, a role which Jesus himself accepted according to Luke 4:17-21.
The Book of Isaiah has been immensely influential in the formation of Christianity, from the devotion to the Virgin Mary to anti-Jewish polemic, medieval passion iconography, and modern Christian feminism and liberation theology. The regard in which Isaiah was held was so high that the book was frequently called "the Fifth Gospel", the prophet who spoke more clearly of Christ and the Church than any others. Its influence extends beyond the Church and 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".
Isaiah makes up 27 of the 37 quotations from the prophets in the Pauline epistles, and takes pride of place in the Gospels and in Acts of the Apostles. Isaiah 7:14, where the prophet is assuring king Ahaz that God will save Judah from the invading armies of Israel and Syria, forms the basis for Matthew 1:23's doctrine of the virgin birth, while Isaiah 40:3-5's image of the exiled Israel led by God and proceeding home to Jerusalem on a newly constructed road through the wilderness was taken up by all four Gospels and applied to John the Baptist and Jesus.
Isaiah seems always to have had a prominent place in Hebrew Bible use, and it is probable that Jesus himself was deeply influenced by Isaiah. Thus many of the Isaiah passages that are familiar to Christians gained their popularity not directly from Isaiah but from the use of them by Jesus and the early Christian authors - this is especially true of the Book of Revelation, which depends heavily on Isaiah for its language and imagery.