Who was the author? The Holy Spirit inspired the prophecy of the book of Amos through a Bethlehem-area shepherd turned prophet named Amos.
What is the book? The book is God's prophecy through Amos primarily to the northern kingdom of Israel but also to southern kingdom of Judah.
Where was it written? Being from Judah, Amos may have remained in Judah, but, given how much of his prophecy is directed at Israel, he may have prophesied in Israel as well, and, since Amos's work ended before the Assyrian exile, there's no reason that I know of to believe he did not finish his work in Israel.
When was it written? Amos dates his work to a kings of Judah and Israel, and approximate dates of 760-750 B.C. are sometimes placed on Amos's work.
Why? As Judah and Israel prospered, their increasing idolatry and other immorality were accompanied by corruption of the judiciary and oppression of the poor, so Amos was sent to announce the nearing end of God's patience.
How? Amos places a special emphasis on justice and reverses the prophets' usual order of judgment on God's people followed by judgment on the nations. Even as Amos gives an exceedingly bleak picture of the nation's impending doom, he also does promise that David's house will be revived and Israel restored.
For further reading on the book of Amos:
- Keil, C.F. and F. Delitzsch. Biblical Commentary on the Old Testament, Volume X: Minor Prophets , translated by James Martin and published as two volumes in one. Grand Rapids, Michigan: William B. Eerdmans Publishing Company, reprinted March 1986. (There are some 104 pages on Amos.)
- Kretzmann, Paul E. Popular Commentary of the Bible: The Old Testament, Volume II, The Poetical and the Prophetical Books. St. Louis: Concordia Publishing House, 1924. (This volume, one that is in our Grace library, has 12 pages on Amos.)