A Brief Overview
Isaiah in conventional dating prophesied for about 50 years from ca. 740 to 690 BCE.
According to the Talmud, Isaiah son of Amoz was the brother of King Amaziah of Judah (father of King Uzziah) and the father-in-law of Hezekiah. King Manasseh of Judah was his grandson and also his executioner (Talmud, Yevamot 49b).
Isaiah lived for 120 years (Agadat Breishit 14, Chasidah).
Isaiah was therefore himself of royal blood of the House of David.
The teachings of Isaiah influenced the early Zoroastrian religion of Iran some of whose texts resembles translations of Isaiah.
See our article:
What Spake Zarathustra?
http://britam.org/zarathustra.html
The prophets Isaiah, Hosea, Amos, Micah, all lived in the same era.
The name Isaiah in Hebrew is "Yeshiyahu" meaning the "The LORD Saves".
Isaiah speaks of Judah and Israel (the Ten Tribes). The emphasis is more on Judah though much concerning the Ten Tribes and their future history is also given.
Other nations are discussed as well, such as the Philistines, Damascus, Elam, Media, Edom, etc.
A Midrash (Pesikta Rabah 33;25).says that Isaiah prophesied concerning all nations of the earth.
The warnings of Isaiah were not heeded but Perhaps they were not meant to be?
Prophecies often have several applications.
Isaiah is important because of his Prophecies concerning the Present-Day End Times rather than their applicability to his own era.
See:
Prototypical Prophecies. Recurring Patterns and Historical Cycles
http://hebrewnations.com/articles/bible/proto.html
The Book of Isaiah has 66 chapters. He speaks of many issues in a concise yet powerful manner. The work is therefore difficult to summarize though an outline is given below.
Outlines of Isaiah
http://www.britam.org/isaiah/ProphSumContents.html
Isaiah Summary chs. 1 to 10
Isaiah Prophecies: Disaster is Coming. We must repent! Only a Tenth will remain! Our leaders have mislead us. Conspiracy Theories are Condemned; Assyria is a tool of Retribution.
Isaiah Summary chs. 11 to 20
The Messiah son of David will come. Judah and Israel will be ingathered. Crossing the Bosporus. Europe, Edom, and Babylon will be punished. Judah and Ephraim will unite and expel the Palestinians. Moab subdued; Lucifer son of the Morning.
Isaiah Summary chs. 21 to 25
Babylon will fall. Tyre is destroyed and its Phoenician inhabitants flee first to Cyprus then to Spain and the west. The Exiled Israelites will call to God from the British Isles and from the West. Abandoning the Covenant and the Law brings Calamity. God will save HIS people. The Almighty will rule over the world and change the course of nature.
Isaiah Summary chs. 26 to 30
In our hearts we always worshipped the One God even though superficially we went after idols. There will be a Resurrection of the Dead. The Whole of the Promised Land will belong to Israel. All the Jews of Judah and all the Israelites from the Lost Ten Tribes will return. Disaster will have overtaken Ephraim but a remnant will repent and be saved. Judah will suffer for not keeping the Law as much as it should have been kept. Nature will change. The Assyrians and all other enemies of Israel will be punished.
Isaiah Summary chs. 31 to 35
God is a Zionist. They who make peace with the heathen will bring disaster. Calamity will occur to Israel. God will protect and guide they who submit themselves to HIM. Begin the journey and the Almighty will inspire his people how they should act. Human nature will change and things will be better.
Isaiah Summary chs. 36 to 40
The Assyrians under Sennacherib beseige Jerusalem. The Assyrian emissary Rabshakeh is an apostate son of King Hezekiah. 185,000 Assyrian soldiers are killed at night by the Angel. Sennacherib returns to Nineveh and is assassinated by his sons. The enemies of Judah are the enemies of the Almighty. God will watch over His people. Som say that this event was a foreshadowing of the Wars of Gog and Magog.
Isaiah Summary chs. 41 to 45.
Israel is at the ends (geographical extremities) of the earth and in the Island. Israel must return to the Almighty. God is pleading with us to return to Him (Isaiah 43:26). Israel will return. Israel will have transported African slaves in chains, possessed the Suez Canal and India and vast resources. Israel will be called names derived from Jacob such as Yank, Union Jack, Jock. By returning to God all the Seed of Israel shall be justified and find glory.
Isaiah Summary chs. 46 to 50
The gods of Babylon along with its people will be destroyed. The persecutors of Judah will be punished. The Lost Tribes of Israel will be in the Isles, at the geographical extremities of the earth and a Brit-Am meaning a convenant of nations. Israel will free the slaves and settle desolate heritages. The Tribes of Jacob must guide the rest of humanity, be a "light to the nations". Judah will be loathe to accept the Lost Ten Tribes, nevertheless there will be a reconciliation. Judah will be compensated for its suffering. Do good and God will reward you.
Isaiah Summary chs. 51 to 55
The Ten Tribes in the Isles will anticipate the Almighty. The Ten Tribes must realize who they are and acknowledge the Almighty. The Jews bore the sins of others and were blamed for the faults of the Gentiles. The Messiah will be a descendant of David from the Tribe of Judah. Everything can be made better than it is. We must believe in our own potential to do good to ourselves and to others.
Isaiah Summary chs. 56 to 60
We must keep the Sabbath and act righteously, doing justice and good deeds. The Oppressors of Judah will be shown the error of their ways. God will always be with HIS people even when they are not aware of it. The Lost Ten Tribes will be in the Isles of the Sea and the West. First Judah will return then the Ten Tribes in stages. The return will be by air travel.
Isaiah Summary chs. 61 to 66
There will be a restoration of Judah and Israel. The bad will be punished and the good rewarded. They who did the best they could will be saved. Members of the Tribes of Israel will be informed who they are and what Tribe they belong to. Their Israelite Ancestry will be acknowledged. The Temple must be rebuilt and Israel restored for our own sakes. Those who were lost amongst the Gentiles will be brought back. The good amongst the Gentiles will be rewarded. Nature will change. A Resurrection of the Dead will take place.