Who was the author? The Holy Spirit inspired Moses to record the bulk of the book we know as Deuteronomy, although Joshua or a later editor or two likely added some content and made a few revisions.
What is the book? The book is essentially Moses's final sermon to the people of Israel, recapping the story of their deliverance from Egypt and reiterating God's covenant with them, including blessings for their faithfulness and curses for their unfaithfulness.
Where was it written? The sermon was delivered and the book likely recorded on the plains of Moab at the Jordan River.
When was it written? A usual date for the end of the 40-year wilderness wanderings is 1406 B.C., so we would date the delivery of the sermon and the writing of the book around that time.
Why? The people were renewing the covenant God had made with their forebears and with them, and the sermon/book provides not only details of that covenant but also its rationale.
How? Some scholars say the structure of Deuteronomy reflects the structure of treaties of the day used by other kings; regardless, its structure serves well its purpose of emphasizing God's covenant of love and grace with the people.
For further reading on the book of Deuteronomy:
- Keil, C.F. and F. Delitzsch. Biblical Commentary on the Old Testament, Volume III, The Pentateuch, translated by James Martin and published in one volume with the other two on the Pentateuch. Grand Rapids, Michigan: William B. Eerdmans Publishing Company, reprinted May 1986. (The section dealing with Deuteronomy, "The Fifth Book of Moses", runs 261 pages. After my study Bible, this is what I turn to next, but it is a somewhat harder to use more-scholarly commentary.)
- Kretzmann, Paul E. Popular Commentary of the Bible: The Old Testament, Volume I, The Historical Books of the Old Testament: Genesis to Esther. St. Louis: Concordia Publishing House, 1923. (Like our Grace library, I have this volume on my shelf, and, although I didn't pull it down at all while blogging on Deuteronomy this time through, I would think you would find its 59 pages on Deuteronomy somewhat helpful and generally accessible. The format runs the text in bold with the comments immediately following the relevant text, so you can in effect read the whole text and his conveniently-placed comments, if you like that format.)