The books of the Later Prophets occur concurrently with those of the Early Prophets. Occasionally, we will see familiar stories from a new perspective. (Compare Isaiah's visit to the ill King Hezekiah in II Kings chapter 20 with Isaiah 38 for one such example.) Isaiah prophesied during the reigns of Uzziah (Azariah), Yosam, Achaz and Hezekiah, though the prophecies in the book are not in chronological order. Some of his contemporary prophets were Nachum, Yoel and Habakkuk, who prophesied to Hezekiah's son, Menashe. (Menashe was the king who had Isaiah executed - see Talmud Yevamos 49b.)
Isaiah is different from most other books of the Prophets in a significant way. Most of the prophets wrote down their own prophecies when they had finished the active part of their careers. Isaiah, however, was assassinated. Since he died abruptly, he was unable to write down his own prophecies. Since they were recorded by different students, there are some stylistic differences in the book. Bible critics attribute this to "two Isaiahs," but this is unnecessary, since our tradition already addresses the authorship of the book and resolves this perceived difficulty before it even arises.
Much of what we know about the Moshiach and the Messianic era comes from the Book of Isaiah. (Chapter 11 is a major source of such information.) However, there has also been much misrepresentation of the book by other religions' missionaries. For example, the alleged prediction of a virgin birth in chapter 7 and the famous "suffering servant" of chapter 53. We will address these mis-interpretations as they arise in the text.
Finally, when Isaiah chastises the nation for their sins, don't get the misimpression that every single person must have necessarily been guilty of these shortcomings. We can all name the sins of our era, but we are also aware that not everybody is guilty of them. Similarly, in Isaiah's time, there were certain misbehaviors that were rampant, but they were by no means universal. (So, when he compares the nation to Sodom, don't take it too literally.)
The Neviim Acharonim are a completely different experience from Chumash and the Neviim Rishonim. If you haven't been exposed to them before, you're about to embark on a unique journey of Torah learning.
Start Isaiah with the OU's Shoshana Grossman Nach Yomi here.