Who was the author? We accept that Isaiah, son of Amoz, principally wrote the book that bears his name and that makes him be regarded as the greatest of the writing prophets.
What is the book? The first of the so-called "latter" or "major" prophets, the book of Isaiah primarily recounts prophecies God gave through Isaiah.
Where was it written? Isaiah's prophecies were most likely written down in Jerusalem, the capital city of Judah, the southern kingdom.
When was it written? Isaiah began his work as a prophet in the year King Uzziah died (probably 740 or 742 B.C.), probably had his zenith under Hezekiah, and may have ended it during the reign of Manasseh, when an unsubstantiated but credible Jewish tradition says he was sawed in half while inside a hollow log (confer Hebrews 11:37). Thus, Isaiah likely served as a prophet around the same time as Amos, Hosea, and Micah. The precise dates the various prophecies were recorded are harder to set.
Why? God through Isaiah pronounces condemnation on His people for their sin and warns them of coming judgment and consequences of that sin, but through Isaiah God also declares a message of comfort and hope to His people, telling of the Servant, the Christ, Who will deliver them from their sin and its judgment if they only believe.
How? Writing both prose and poetry, the Divinely-inspired Isaiah uses a variety of literary devices to warn and comfort in his book. For examples, we find Isaiah personifying inanimate and other objects, using sarcasm, making plays on words, and alluding to events from earlier in Israel's history. As much judgment, death, and destruction Isaiah foretells, we must not forget that for believers life and salvation comes through that same judgment.
For further reading on the book of Isaiah:
- Keil, C.F. and F. Delitzsch. Isaiah, volume VII of their Commentary on the Old Testament in Ten Volumes, translated by James Martin and published as one book. Grand Rapids, Michigan: William B. Eerdmans Publishing Company, reprinted January 1986. (What I consult first, but a somewhat hard to use more-scholarly commentary, although generally right on the money, as they say.)
- Leupold, Herbert Carl. Exposition of Isaiah. Grand Rapids, MI: Baker Book House, 1971. (I have not consulted it, but I am told it is very good.)